The report is prepared for the general information of shareholders. It is authorized for distribution to prospective investors only when preceded or accompanied by a current prospectus.

Table of Contents

LETTER FROM THE EXECUTIVE CHAIR

The opinions expressed in this letter are subject to change and may not be relied upon for investment advice. No forecasts can be guaranteed.

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Table of Contents

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

From time to time Cash & Cash Equivalents may be negative due to timing of cash receipts.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

3

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

4

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

5

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

6

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

From time to time Cash & Cash Equivalents may be negative due to timing of cash receipts.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

7

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

8

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

9

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Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

10

Table of Contents

Portfolio Composition – continued

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. MFS endeavors to fully invest all MFS funds-of-funds in underlying funds on a daily basis. Any divergence from 0.0% in Cash & Cash Equivalents is typically due to the timing of fund subscriptions/redemptions and the settlement of subsequent investment in/divestment from the underlying funds. While the MFS funds-of-funds’ subscriptions/redemptions are processed at the same day NAV of the underlying funds, a positive/negative cash balance will be reflected on the MFS funds-of-funds’ Statements of Assets and Liabilities until the trades with the underlying funds settle, which is typically two business days. Please see the Statements of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

From time to time Cash & Cash Equivalents may be negative due to timing of cash receipts.

Percentages are based on net assets as of April 30, 2020.

The portfolio is actively managed and current holdings may be different.

11

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MANAGEMENT REVIEW

MFS Lifetime Funds

Market Environment

Market volatility soared at the end of the period as COVID-19, the illness caused by the novel coronavirus first detected in China, spread around the world in early 2020. Government-imposed social distancing measures taken to slow the spread of the virus forced the shutdown of large portions of the global economy. In an attempt to limit the economic fallout of the crisis, central bankers and policymakers have taken a variety of actions unprecedented in both size and speed, but despite their best efforts, a global recession has begun. Given the unique circumstances surrounding the genesis of the downturn, it is difficult to forecast how long the crisis will linger.

High levels of investor uncertainty saw equity prices plunge, market volatility rise and large segments of global fixed income markets freeze as investors sought liquidity wherever they could find it. As the global economy rapidly slowed, a disagreement between Saudi Arabia and Russia over OPEC+ production cuts resulted in the Saudis shelving the OPEC+ arrangement and increasing oil output at the same time that global oil demand was plummeting, which compounded market turmoil. The resulting drop in prices undercut oil exporters, many of which are in emerging markets, as well as a large segment of the high-yield credit market.

Central banks around the world responded quickly and massively to the crisis with programs to improve liquidity and support markets. They proved largely successful in helping to restore market function, easing volatility and stimulating a market rebound at the end of the period. Monetary easing measures were complimented by large fiscal stimulus plans in developed countries. Even emerging market countries were able to implement counter-cyclical policies, a departure from the usual market-dictated response to risk-off crises, due to relatively manageable external liabilities and balance of payments in many countries and persistently low inflation.

As is often the case in a serious crisis, market vulnerabilities have been revealed. For example, companies that have added significant leverage to their balance sheets in recent years by borrowing to fund dividend payments and stock buybacks may find it difficult to follow that path in the future, and investors may not reward them if they do. Recapitalizations by some of these highly leveraged firms could dilute existing shareholders. Very long supply chains designed to squeeze out every bit of savings may be shifted closer to home markets if companies seek to emphasize resiliency over cost after a series of supply disruptions. The aftereffects of the global pandemic could impact consumer, business and government behavior in ways it will be difficult to forecast.

MFS Lifetime Income Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime Income Fund (fund) provided a total return of 2.78%, at net asset value. This compares with a return of 10.84% for the fund’s benchmark, the Bloomberg Barclays U.S. Aggregate Bond Index. The fund’s other benchmark, the MFS Lifetime Income Fund Blended Index (Blended Index), generated a return of 6.74%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets.The fund’s broad diversification across fixed income funds was a notable detractor from relative performance, as diversification away from the US rates market and into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Limited Maturity Fund and the MFS Total Return Bond Fund, were among the fund’s top relative detractors.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, both the MFS Research International Fund and MFS International Intrinsic Value Fund helped relative returns as the funds performed well within their respective markets. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2020 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2020 Fund (fund) provided a total return of 2.46%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2020 Fund Blended Index (Blended Index), generated a return of 6.51%. The Blended

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Management Review – continued

Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. The fund’s broad diversification across fixed income funds was a notable detractor from relative performance, as diversification away from the US rates market and into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Limited Maturity Fund, MFS Total Return Bond Fund and MFS High Income Fund, were among the fund’s top relative detractors.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, both the MFS Research International Fund and MFS International Intrinsic Value Fund helped relative returns as the funds performed well within their respective markets. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2025 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2025 Fund (fund) provided a total return of 1.25%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2025 Fund Blended Index (Blended Index), generated a return of 4.86%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to both bond funds and US stock funds were notable detractors from performance.

Within the fixed income segment of the fund, diversification away from the US rates market and into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Limited Maturity Fund, MFS High Income Fund and MFS Total Return Bond Fund, were among the fund’s top relative detractors.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, both the MFS Research International Fund and MFS International Intrinsic Value Fund helped relative returns as the funds performed well within their respective markets. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2030 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2030 Fund (fund) provided a total return of –1.36%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2030 Fund Blended Index (Blended Index), generated a return of 1.73%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to bond funds and US stock funds were notable detractors from performance.

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Management Review – continued

Within the fixed income segment of the fund, most of the underlying funds underperformed their respective market segments during the reporting period. The fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS High Income Fund, were among the fund’s top relative detractors.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, both the MFS Research International Fund and MFS International Intrinsic Value Fund helped relative returns as the funds performed well within their respective markets. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2035 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2035 Fund (fund) provided a total return of –4.23%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2035 Fund Blended Index (Blended Index), generated a return of –1.42%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to US stock funds and bond funds were notable detractors from performance.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

Within the fixed income segment of the fund, most of the underlying funds underperformed their respective market segments during the reporting period. The fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS High Income Fund and MFS Emerging Market Debt Fund, were among the fund’s top relative detractors.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, the MFS International Intrinsic Value Fund, MFS Research International Fund and MFS International Growth Fund helped relative returns. Within specialty funds, MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2040 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2040 Fund (fund) provided a total return of –5.08%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2040 Fund Blended Index (Blended Index), generated a return of –2.96%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to US stock funds and bond funds were notable detractors from performance.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

Within the fixed income segment of the fund, most of the underlying funds underperformed their respective market segments during the reporting period. The fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS High Income Fund and MFS Emerging Market Debt Fund, were among the fund’s top relative detractors.

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Management Review – continued

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, the MFS International Intrinsic Value Fund, MFS Research International Fund and MFS International Growth Fund helped relative returns. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2045 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2045 Fund (fund) provided a total return of –5.93%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2045 Fund Blended Index (Blended Index), generated a return of –4.26%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to US stock funds was a notable detractor from performance.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

Within the fixed income segment of the fund, the fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Total Return Bond Fund, were among the fund’s top relative detractors.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, the MFS International Intrinsic Value Fund, MFS International Growth Fund and MFS Research International Fund helped relative returns. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2050 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2050 Fund (fund) provided a total return of –5.93%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2050 Fund Blended Index (Blended Index), generated a return of –4.26%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to US stock funds was a notable detractor from performance.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

Within the fixed income segment of the fund, the fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Total Return Bond Fund, were among the fund’s top relative detractors.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, the MFS International Intrinsic Value Fund, MFS International Growth Fund and MFS Research International Fund helped relative returns. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2055 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2055 Fund (fund) provided a total return of –5.87%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index.

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Management Review – continued

The fund’s other benchmark, the MFS Lifetime 2055 Fund Blended Index (Blended Index), generated a return of –4.26%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to US stock funds was a notable detractor from performance.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

Within the fixed income segment of the fund, the fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Total Return Bond Fund, were among the fund’s top relative detractors.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, the MFS International Intrinsic Value Fund, MFS International Growth Fund and MFS Research International Fund helped relative returns. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

MFS Lifetime 2060 Fund

Summary of Results

For the twelve months ended April 30, 2020, Class A shares of the MFS Lifetime 2060 Fund (fund) provided a total return of –5.83%, at net asset value. This compares with a return of 0.86% for the fund’s benchmark, the Standard & Poor’s 500 Stock Index. The fund’s other benchmark, the MFS Lifetime 2060 Fund Blended Index (Blended Index), generated a return of –4.26%. The Blended Index reflects the blended returns of equity and fixed income market indices, with percentage allocations to each index designed to resemble the equity and fixed income allocations of the fund. The market indices and related percentage allocations used to compile the Blended Index are set forth in the Performance Summary.

Factors Affecting Performance

During the reporting period, on an absolute basis, fixed income markets outperformed equity markets. On a relative basis, the fund’s allocation to US stock funds was a notable detractor from performance.

Within US stock funds, the fund’s investments in middle and small capitalization strategies, as well as value funds, generally underperformed but were partially offset by the fund’s investments in growth strategies, which outperformed.

Within the fixed income segment of the fund, the fund’s diversification into credit and global markets generally held back performance. Further, underlying funds that tend to be overweight credit versus their respective market segments, such as the MFS Total Return Bond Fund, were among the fund’s top relative detractors.

The fund’s allocation to international stock funds and specialty funds positively affected relative performance. Within international stock funds, the MFS International Intrinsic Value Fund, MFS International Growth Fund and MFS Research International Fund helped relative returns. Within specialty funds, the MFS Global Real Estate Fund supported relative performance as the fund performed well within the global real estate market segment and outweighed the negative impact from investments in the MFS Commodity Strategy Fund which underperformed the commodity market segment during the reporting period.

Respectfully,

Portfolio Manager(s)

Joseph Flaherty and Natalie Shapiro

The views expressed in this report are those of the portfolio manager(s) only through the end of the period of the report as stated on the cover and do not necessarily reflect the views of MFS or any other person in the MFS organization. These views are subject to change at any time based on market or other conditions, and MFS disclaims any responsibility to update such views. These views may not be relied upon as investment advice or an indication of trading intent on behalf of any MFS portfolio. References to specific securities are not recommendations of such securities, and may not be representative of any MFS portfolio’s current or future investments.

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PERFORMANCE SUMMARY THROUGH 4/30/20

The following charts illustrate a representative class of each fund’s historical performance in comparison to its benchmark(s). Performance results include the deduction of the maximum applicable sales charge and reflect the percentage change in net asset value, including reinvestment of dividends and capital gains distributions. The performance of other share classes will be greater than or less than that of the class depicted below. Benchmarks are unmanaged and may not be invested in directly. Benchmark returns do not reflect sales charges, commissions or expenses. (See Notes to Performance Summary.)

Performance data shown represents past performance and is no guarantee of future results. Investment return and principal value fluctuate so your shares, when sold, may be worth more or less than the original cost; current performance may be lower or higher than quoted. The performance shown does not reflect the deduction of taxes, if any, that a shareholder would pay on fund distributions or the redemption of fund shares.

MFS Lifetime Income Fund

Growth of a hypothetical $10,000 investment

Average annual total returns through 4/30/20

Without sales charge

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Performance Summary – continued

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

18

Table of Contents

Performance Summary – continued

MFS Lifetime 2020 Fund

Growth of a hypothetical $10,000 investment

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

19

Table of Contents

Performance Summary – continued

20

Table of Contents

Performance Summary – continued

MFS Lifetime 2025 Fund

Growth of a hypothetical $10,000 investment (t)

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

21

Table of Contents

Performance Summary – continued

22

Table of Contents

Performance Summary – continued

MFS Lifetime 2030 Fund

Growth of a hypothetical $10,000 investment

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

23

Table of Contents

Performance Summary – continued

24

Table of Contents

Performance Summary – continued

MFS Lifetime 2035 Fund

Growth of a hypothetical $10,000 investment (t)

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

25

Table of Contents

Performance Summary – continued

26

Table of Contents

Performance Summary – continued

MFS Lifetime 2040 Fund

Growth of a hypothetical $10,000 investment

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

27

Table of Contents

Performance Summary – continued

28

Table of Contents

Performance Summary – continued

MFS Lifetime 2045 Fund

Growth of a hypothetical $10,000 investment (t)

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

29

Table of Contents

Performance Summary – continued

30

Table of Contents

Performance Summary – continued

MFS Lifetime 2050 Fund

Growth of a hypothetical $10,000 investment (t)

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

31

Table of Contents

Performance Summary – continued

32

Table of Contents

Performance Summary – continued

MFS Lifetime 2055 Fund

Growth of a hypothetical $10,000 investment (t)

Average annual total returns through 4/30/20

Without sales charge

CDSC – Contingent Deferred Sales Charge.

Class I, R1, R2, R3, R4, and R6 shares do not have a sales charge.

33

Table of Contents

Performance Summary – continued