When Thunderbird's calendar broke

Events weren't displayed properly in Thunderbird email client and its Lightning calendar plugin, for two weeks. There were complaints.

To fix it, manually download a previous version of Thunderbird (24.0) and its associated old version of Lightning (2.6).

(Missing step here regarding how to have Synaptic recognise an old version of Thunderbird. Disabling upgrade in Synaptic may not be necessary if Thunderbird is run outside of any package manager)

Then fix them both so they don't upgrade automatically:

• Use Synaptic package manager to find Thunderbird, the click the 'Package' menu and select 'Lock Version'.
• For Lightning, go to Add-ons, Extensions, right-click Lightning and 'Show more information', then switch off 'Automatic Updates'.

After a while, the developers will probably fix it. After that happens, you can unlock the packages and upgrade again.

It's times like this that make me appreciate Microsoft Outlook :(