I have a video here of the whole migration.
If your running a version lower then 220.127.116.11 you need to upgrade to 18.104.22.168. You can see your version of lansweeper after you login by going to Configuration -> Your Lansweeper License
Go to your Lansweeper program directory (typically C:\Programs (x86)\Lansweeper) and backup 2 Folders SQLData and Key. Key has your encryption key (if enabled) and SQLData has your SQL COMPACT and SQL Express databases (SQL Express only after you have upgraded to version 22.214.171.124)
You can read about the entire process from this Lansweeper KB
Lansweeper has done a great job automating this, after you upgrade to version 126.96.36.199 your database will be converted, it takes about 5 minutes. Once the installer has finished you will see a new service called Lansweeper LocalDB Service.
To upgrade to version 8 download the lastest version of Lansweeper https://www.lansweeper.com/update-lansweeper/ and repeat the steps from the beginning of the blog but save the SQLDATA and Key to the 8013014 directory. Once done you will be on the latest version of lansweeper (at the time of this post). The version of SQL Express Lansweeper is using is version 2014.
After this update I had an issue with email tickets being 10 tickets lower then the last Lansweeper ticket. To fix the issue I reset the ticket id counter as described in https://www.lansweeper.com/knowledgebase/resetting-the-ticket-id-counter/