The Command "/gridtorio-version" returns the same version as when the save was started (in this case 0.0.8) even if the mod has been updated to a newer version.
If i start a new save or press "restart" to reset the current map then it will announce version number 0.2.0 in chat and the command will also return this version.
Seems like something about how the Mod keep track of this variable and access it allows it to get "stuck" on a specific version number.

This isn't quite a bug. The reason why it still says 0.0.8 on saves that were created with the version 0.0.8 is because save files are not updated with the updating of a mod that distributes scenarios. The mod itself would have to make changes to the save so that the old scenario is updated to the current version, which takes an extremely large amount of work from what it seems like, but maybe I'm mistaken. I'll look into this over time. For now, it kind of sucks, but you have to start a new game for every new version that you want to play on. Besides, the scenario will, within the next week, reach version 1.0.0, after which point updates will be far less frequent, so this problem becomes a bit less relevant. Updates for bug fixes may include some kind of migration logic from the mod itself (separate from the scenario) so that older saves (from 1.0.0 and onward) can receive the bug fixes. But also, with the way that scenarios work in the game, it might not even be possible without direct file management outside of the game.

this prompted me to look a little around regarding updating a scenario.
im not entirely confident about it since i never ended up in a situation where one of my mods needs to update a scenario but from what i can tell if the scenario file is within the mods directory and you updated the scenario you can do exactly "game.reload_script()" after checking if the mod version matches with the scenario version to force a reload of scenario scripts from the original scenario file because otherwise factorio will on existing saves always just load the script from the save file.
Turns out someone several years ago had a similar need to this situation and asked the same question on the forum.

Wow, this is extremely helpful. Thank you very much for informing me about this. I was under the conviction that Wube didn't add anything like that for certain reason like preventing data corruption or something. But thank you, and thank you to Wube! I will immediately look into implementing this, since it is highly requested quality of life.