The core modules are no longer versions as e.g. 6.d, so checking for 6.c+ no longer makes sense. We could technically pin it on the 20XX.XX.X type versions rakudo is using, but that will require more consideration by myself (other compilers may not version them similarly, although they would have had to follow the original v6.c versioning), and commitment to a consistent versioning schema by Rakudo for its core modules.
The core modules are no longer versions as e.g. 6.d, so checking for 6.c+ no longer makes sense. We could technically pin it on the 20XX.XX.X type versions rakudo is using, but that will require more consideration by myself (other compilers may not version them similarly, although they would have had to follow the original v6.c versioning), and commitment to a consistent versioning schema by Rakudo for its core modules.