Skipping straight to a June 2021 update would fail because the update’s manifest required at least build 14393.970.
: Sourced from the SW_DVD9_Win_Svr_STD_Core_and_DataCtr_Core_2016_64Bit_English_-2_MLF_X21-22843 media, it supported both Standard and Datacenter editions. windows server 2016 build 14393970 enus april 2017 2021
Some notable fixes and changes in the April 2017 update for Windows Server 2016 include: Skipping straight to a June 2021 update would