Also, I would suggest you to install on server - Sourcemod 1.9, and check how your RPG build will work there (without syntax updating yet).
Then upgrade to SM 1.10, and check again. Should work normally unless you are using some specific things, like manual calculation of datapack cells position ..., some deprecated func, e.t.c., not remember all, need to read
major release changelog for 1.9 & 1.10.
If some problems occur, firstly make it work correctly on SM 1.10 (but compiled with old syntax yet on 1.7 compiler), or at least you will know which "logical errors in code" needs attention while updating syntax.
And only after that try to update the syntax.
Just my personal opinion.
P.S. As about SM 1.11, it has even more limitations related to code parser (on sourcepawn side).
I think that it makes no sense to focus on it at the moment (while updating old syntax), since the parser still undergoing changes and contain some bugs unlike SM 1.10.