It should be possible to have individual user limits.
A field should be added to the user entity, where you can provide an individual session limit.
The proposed solution has been implemented, reviews are needed.
When editing a user profile, assuming appropriate permissions are set, an integer input field is provided where the total number of simultaneous active sessions can be set. In case there is no value provided, the original limits according to the user's roles are applied. In case the value 0 is entered, no restrictions are enforced on the number of sessions the user can have.
Integer base field has been added to user entities.
Needs review
2.0
Code
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
OK I have rebased the PR based on 2.x. However, 2.x is actually behind the latest release 2.0.2. So once 2.x branch is updated we'll want to re-roll.
In the mean time, I have created a patch against 2.0.2.
Marking RTBC as this appears to be working as expected and next steps are on the maintainers to update the 2.x branch (and can probably easily merge without much effort.)