Can I ask question about nsis-web with differential updater?

Does nsis-web support differential updater?  I didn't find MyApp-0.0.0-x64.nsis.7z.blockmap after build.  Is there some document to instruct how to deploy it?

And, is there a max size to generate block map of the 7z?  It failed to build when the 7z exceeds 2G size by using nsis.