Hi
There is access to as many T1134 supplements as needed in the T1 module. The T1134 summary can report more than 17 T1134 supplements. There does not seem to be a limit to the T1134 electronic filing size. The Attach a Doc in the T1 module is used to send documents to the Ministry of Revenue Quebec(RQ): it is not able to send documents to CRA.
There is also not an FRRMS submission application in the T1 module.
