Confirming of family group invite without app. How?

[Kouzelník Pokustón]

First. Im using ASF for years, I never used real steam app cause i really hate useles apps, and i had no smartphone when steam first time forced steam guard for trades, so ASF was obvious choice.

Second. Steam says something about mobile confirmation when i try to accept invitation. ASF seems to dont support this feature atm, sadly.

Is there any way to do this throught SMS, mail, any ♥♥♥♥♥♥♥♥♥ socnet, tubepost, tamtams anyhow?