This was the SHA2 signing update, released in March, 2015. Per the MS Catalog at https://www.catalog.update.microsoft.com/Search.aspx?q=KB3033929 , the update has been replaced by a number of other updates, including
2019-06 Security Only Quality Update for Windows Server 2008 R2 for x64-based Systems (KB4503269)
2018-08 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4343900)
2019-08 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4512506)
2019-11 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4525235)
November, 2016 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB3197868)
2019-01 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4480970)
2018-09 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4457144)
2019-12 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4530734)
2020-01 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4534310)
2020-02 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4537820)
2020-03 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4540688)
2020-04 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4550964)
2020-05 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4556836)
2020-06 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4561643)
2020-07 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4565524)
2020-08 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4571729)
2020-09 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4577051)
2020-08 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4571729)
2020-10 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4580345)
2020-11 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4586827)
2020-12 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4592471)
2021-01 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4598279)
2021-02 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4601347)
2021-03 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB5000841)
I see KB4503269 and KB4534310 in “Patches for Windows”, applying either of those should provide the update (the first may be a prerequisite for the second, since it introduced the SHA2 signing update).
