Pydis is a python disassembler, it can be a replacement for cpython's
Lib/dis.py.
Pydis supports all the cpython versions above 2.5, every verion above 2.5 supports other versions. This means, pydis decodes 2.6 bytes code in 3.6 and vice versa.
Python's dis moduel is super helpful for looking inside code objects, but it
won't support other python versions. If the code object is created through
python 3.5 and try to disassemble with python3.6, it won't work.
Each python version gets changes to opcodes, there will be ne ones added and few are deleted. Unless you recreate the code object with new python version, the same code object can't be interpreted with old versions.