Well we do have a more recent firmware: 2.1.9(3). You can follow the instructions to update to it:
https://openthings.freshdesk.com/support/solutions/articles/5000832310-opensprinkler-3-x-firmware-update-guide
We don’t have resources to test the controller exhaustively with all wifi routers. There might be wifi routers that don’t work very well with the wifi chip. I really don’t have enough knowledge to tell.