Just for the record: on iOS, you don’t need the socks5 support in case you want to use email over an onion service (tor).
All you need is to install Orbot iOS (external Link to the app store).
Orbort iOS automatically starts a VPN and routes all traffic into tor’s socks5 interface.
You need to adjust the account settings accordingly. During the account setup tap on
→ LOG INTO YOUR E-MAIL ACCOUNT
→ Advanced
→ enter the onion service address for IMAP at IMAP Server
→ enter the onion service address for SMTP at SMTP Server
You can also change adapt the settings of an already configured account by tapping on
→ Settings
→ Your Profile Info
→ Password and Account
→ Advanced
→ IMAP Server and SMTP Server
Please check your providers instructions if further configuration changes are required.
Some activist tech collectives supporting email over onion routing are:
Systemli or
Riseup