→Softphones: Voipfone Softphone is working again - maybe because I created a new account ?
* Linphone 4.0.1 (Android)
* Twinkle (Linux) - although currently (Dec 2018) there's a problem with SRV records when using systemd-resolved (on Ubuntu and Debian at least)
* Voipfone Softphone (Android) deserves a mention. It needs an account with voipfone.co.uk, but you can signup and try for free. Their softphone app just works out of the box for calling SIP URIs
(although an update in March 2019 has stopped this working)