Hello,
I have filed a pull request
<https://github.com/gentoo/gentoo/pull/7274> to add Radicale 2.1.8 to
the tree. Migrating from Radicale 1 to 2 requires running a database
export command using Radicale 1, i.e. *before* upgrading, as Radicale 2
can’t read version 1’s storage format. Please see below my proposed
news item to go along with this version bump. Note that I am not a
developer and am therefore unable to commit this myself; I would
appreciate that it be reviewed and then whoever accepts my pull request
also add this news item at the same time. Because of this, I have set
the Posted date to today, as I can’t predict when it will actually be
posted; I ask that the committer please revise the date accordingly.
Thank you!

Title: Radicale 2 requires pre-install migration
Author: Christopher Head <chead@chead.ca>
Posted: 2018-03-01
Revision: 1
News-Item-Format: 2.0
Display-If-Installed: <www-apps/radicale-2

Radicale version 2 uses a new storage format and is not able to read
databases created by version 1. Version 1 releases starting from 1.1.3
include a --export-storage option which can be used to export their
databases in a format that Radicale 2 can use; you must do this before
upgrading to version 2.

Please see the Radicale migration guide for more information:

http://radicale.org/1to2/
-- 
Christopher Head