I think that this bug is already reported now for U18.04.
Bug #1759286 (and Bug #1761844 is probably a duplicate)
Bug #1759286 gives as a solution to install Thunderbird 57.0b2 from Thunderbird PPA.
I have not yet tested it.
I think that this bug is already reported now for U18.04.
Bug #1759286 (and Bug #1761844 is probably a duplicate)
Bug #1759286 gives as a solution to install Thunderbird 57.0b2 from Thunderbird PPA.
I have not yet tested it.