Please do not use the testers repository when you switched to Whonix 11.
It still contains packages for Debian wheezy. But Whonix 11 is based on Debian jessie.
Upgrading these packages from wheezy -> jessie would break existing testers installations. Because if it happens unexpected, those would not go through the special instructions required for Whonix 10 -> 11 upgrades. (https://www.whonix.org/wiki/Upgrading_Whonix_10_to_Whonix_11)
I am not sure yet how to solve this. Either we start providing a jessie-testing repository, which would require being manually added to /etc/apt/souces.list.d/whonix.list [or so]. Or:
whonix_repository --enable --codename jessie-testing
Or we break the normal testers repository after 1 month.
Related, issue “stable-fixes-testers repository required”:
The “stable-fixes-testers” repository (probably gets a different name) is different from the testers repository.