I have been using Thunderbird for the last 2 years and my configuration has always worked well even through the transition of switching from Windows to Linux. I have never had any trouble when updating versions of Firefox so I thought that I wouldn’t have many problems with Thunderbird either. Was it as plain sailing as what I originally thought?
The 1st Upgrade
My choice of upgrade method was to use the Ubuntuzilla script which is what I use for Firefox. Ubuntuzilla backs up your profile folder before making any changes which is an excellent idea when upgrading to a new version. Once I upgraded I loaded up Thunderbird which started fine but I could not see any emails although it said that I was getting them. I tried creating the accounts again but that would not work, then the options page was stuck and I could not get lightning to integrate well. I decided to roll back to the previous version and start again.
Roll Back to V2
I went back to v2, via the same Ubuntuzilla script, I deleted the contents of .thunderbird folder in my home folder and replaced it with the backup files from my Thunderbird backup which the Ubuntuzilla script created. I ran the program and copied all of my emails to my local folders to prevent losing them especially as I haven’t got them saved on the server. I saved my contacts to a .LDIF file and my calendar to a .ICS file so I could easily import them after upgrade. When I had finished exporting I changed the .thunderbird to ThunderbirdBackup (or similar) and ran the Ubuntuzilla script again.
I opened the new Thunderbird up and then shut it down again as this creates the new profile. Navigating to my backup I copied the local folders folder from ThunderbirdBackup/user.default/mail across to the new .thunderbird/user.default/Mail. Setting up new accounts is a breeze now as Thunderbird automatically searches for the email settings. After 5 minutes I had configured all of my emails, 6 in total and they were all in working order. I installed the latest version of lightning, which is the current testing version. I imported my contacts and calendar and all is in good working order.
I have known people that have gone through the installation without any problems but I would definitely recommend you make a backup of your profile before any major upgrade. I would also back up contacts and calendars if used too. However it was definitely worth the hassle as the new version has some excellent features.