setting externalip=<version 3 onion address> results in error

[Liongrass]

Hi all!

I have been running a Bitcoin node reachable via a onion address for a long time. Today I decided to upgrade to a Version 3 address, but encountered an error.

2020-03-03T Error: Cannot resolve -externalip address: 'rn2rjwuxfjzvjfkg2hmrduc2n7tjjpasrlianfskdhhhhfqqvf7kliyd.onion'

My new bitcoin.conf file:

listen=1
externalip=rn2rjwuxfjzvjfkg2hmrduc2n7tjjpasrlianfskdhhhhfqqvf7kliyd.onion

My old bitcoin.conf file:

listen=1
externalip=llljnatksfgtlhko.onion

This works fine: 2020-03-03 AddLocal(llljnatksfgtlhko.onion:8333,4)

Bitcoin Core version:
v0.18.0.0-g2472733a24a9364e4c6233ccd04166a26a68cc65

[sipa]

Yes, Onion v3 addresses are not currently supported. A P2P protocol extension is needed to be able to relay those (see BIP 155).

[laanwj]

Correct, see issue #9214, and PR #16748

[vasild]

This is now implemented and will be included in 0.21.