Since Flexnet publisher 11.19.1 release, there is a new enhancement in Windows Platform Kits

• Introduced a new 64-bit Windows FlexNet Publisher kit with suffix as "_vc16".
• The binaries in the new Windows kit are generated with VS 2019 toolchain. The kit is only supported for VS 2017 and above.
• The FlexNet Publisher still supports the default 32-bit & 64-bit Windows FlexNet Publisher kit without the suffix _vc16.
• It is supported for all VS versions but with legacy binaries support.
• The Windows version of lmadmin has also been upgraded to VS 2019. On Windows, only 64-bit
  lmadmin will be available from now onwards.

Note: This information is documented in FlexNet Publisher 2022 11.19.1 Release Notes page#2