This topic describes new items and changes that affect the 3ds Max 2021 C++ SDK.
3ds Max 2021 is binary backward compatible with 3ds Max 2020. Plugins compiled for 3ds Max 2020 will load and work in 3ds Max 2021.
for 3ds Max 2020 plugins packaged as an Application Package Format, the SeriesMax tag must be 2021 in order for 3ds Max 2021 to load them.
The 3ds Max SDK is available for download for free from the Autodesk Developer Network website. You can also find it on the 3ds Max 2021 cd-image (under \x64\Tools\MAXSDK)."
New features and improvements are described in these topics: