System versioning cannot be based on local timestamps, as it is now

As previously discussed, currently system versioning is based on local (session) timestamps. It cannot be so, because session values can be changed by any user, intentionally or not, so the history is easy for anyone to tamper with.

I'm creating this report to make sure that the issue is addressed before system versioning is released. It doesn't mean it must be fixed before the beta release, but at least the decision must be made on how to deal with it, so that it doesn't turn out that incompatible changes are required which are not allowed for post-beta.