Hi @Boko,
Yes, it should work fine to use ArduSub 4.1 with the Water Linked UGPS, when using it with our Companion software 
There’s also now an extension available for it via the Extension Manager in the latest BlueOS beta image. We haven’t properly tested the extension yet though, so you’re welcome to try it out if you want to but we can’t yet guarantee it will work as expected (please let us know any issues if you do end up trying it!).
By the way, sorry for the delay on this - I asked about it at the time and then forgot to get back to you before I went away.