Roblox Wrapper is a tool which allows you to wrap the Roblox player (and Studio). You can even install old Roblox player versions! (But not use them in live servers) It uses python to control program arguments (and shows you console output) and prevents Roblox from updating.
This is primarily useful for modifying Roblox launch arguments.
Known Bugs
The Roblox launcher attempts to update every launch.
Old player versions
I am currently working on figuring out a way to load into studio servers using old clients since you cannot join live servers. For example, if you have the 2016 client you could connect to a 2016 studio server.
Currently I’ve only tested back to 2016 and the 2016 player needs some of its arguments to be removed to launch (that’s what the legacy option is for). I somehow managed to get flagged for using Fiddler (the error message is very obscure but a few staff subtly talked about it to people experiencing the error and it turns out its most likely related to proxies/fiddler). The problem is no matter what I do the client loads into a black screen now so I never did manage to get it working. I’ve cleared the registry, every cache file (IE included) reinstalled Roblox completely and still cannot find where the flag is stored. The client was up and running for a bit though and I managed to get some screenshots of the 2016 launch screen.