I don't remember when it was added but I was using it with version 22 well more than a year ago and I think it may have been before that but can't be sure.
I took a break from PCB work for a while, changed my laptop and now I have been asked to do some again and Easy-PC complains and won't work with library loader unless I have the latest version of Easy-PC.
Was introduced in V22. Might have something to do with incompatibility caused but subsequent updates to both the Library Loader and EPC.
Mind you it was always possible (pre-V22) to import into EPC from Samacsys albeit the part didn't appear automatically within the EPC environment. But you could download and import using a more long-winded method but it was possible. Just in the same way you can do it with EDA.
EDIT .... Just tried and you can import without using the LL from Samacsys using either Designspark or Eagle imports.