https://labs.riseup.net/code/issues/9713
This links to the bug tracker for Electrum in Tails.
It looks like people are finally getting Electrum 2.5.x working in the Tails environment and that we most likely will see an updated Electrum in the next version of Tails that is due on December 15th (Tails 1.8).
Let's all hope that these devs can make it happen!
An update is very much needed for Electrum to come with Tails.