On Monday June 15, the developers of the Tor Project announced the initial plan for the deprecation of Onion services v2. You can identify v2 addresses easily as they are only 16 character long, where as the v3 addresses are 56 character long.

Why?

The v2 services used RSA1024, where as v3 uses ed25519, means better cryptography. We can also have offline keys for the onion service. You can read all other benefits in the v3 spec.

Timeline

According to the email to the list, the following the current timeline:

• On 2020-09-15 with 0.4.4.x release Tor will start informing v2 onion service operators that v2 is deprecated.
• On 2021-07-15 with 0.4.6.x release Tor will stop supporting v2 onion addresses, and all related source code will be removed.
• On 2021-10-15 there will be a new stable version release which will disable using v2 onion services on the Tor network.

How can you prepare as an Onion service provider?

If you are using/providing any v2 onion service, you should enable v3 service for the same service. This will help you to test your v3 configuration while keeping the v2 on, and then you can retire your v2 address. If you need help in setting authenticated v3 service, you can follow this blog post. I wrote another post which explains how can you generate the keys using Python cryptography module.

Read the full announcement in the list archive.