Merge branch...

Merge branch '3529-pickle-protocol-version-with-compatibility-with-python-3-7-3-8-3-9-3-10' into 'master'

Resolve "pickle protocol version with compatibility with Python 3.7, 3.8, 3.9, 3.10"

Closes #3529 (closed)

See merge request !4965 (merged)

(cherry picked from commit e41315bd)

e5e8fd89 fix issue #3529 (closed): use known pickle protocol version when dumping channel data