forums.wsusoffline.net

I tried moving client folder between older and new version, but not sure if it would be alright

whats the officall way, redownload all updates to avoid potential issues?

You can either unpack the new version over the existing one, overwriting all files in the process (the repository will stay untouched). Or you can copy/move the update directories in wsusoffline\client to the new version. This depends on the updates you downloaded, but mainly these are w*, ofc, o2*, dotnet, cpp, win and wsus. Do not attempt to copy/move the whole client directory because it contains scripts and UpdateInstaller and stuff.

The update procedure is also part of the FAQ in wsusoffline\doc\faq-*.txt.

Regards
Dalai