Trezor on Testnet4 - How to Use Testnet3 with SDK?

Hi all,

Trezor auto-migrated to Testnet4, but I need to use Testnet3 for a third-party wallet via the Trezor SDK. Any way to switch back or configure it for Testnet3? Tips appreciated!

Thanks

It seems like I can connect use electrum server in Trezor Suite but not on Trezor Connect Web. Attached screenshots. Is it possible to set electrum server as custom backend instead of local blockbook server?

connect DOT trezor DOT io SLASH 9 seems to be connecting to Testnet 4. How to have it to talk to Testnet3?

cc @matejcik happy to share more details if needed