Yes, I created the issue before development to have a ticket number for my branch.
I already created DB2400V7R1Dialect with the sequences support (implemented since V5R3 but I can't do tests on this version).

I will create DB2400V7R3Dialect with LIMIT and OFFSET which are available since V7R1 with PTF Group SF99701 level 38 but in *BASE only since V7R3.

I will do a pull request soon.