Translations:Upgrading from a previous version/14/en
From LimeSurvey Manual
Since the data structure and a lot of other things were changed, upgrading from any version previous to v1.50 is NOT possible. If you have old survey structure files with an *.sql extension, the only way to get these into a newer version is to install version 1.50, import the .sql file(s) there, then upgrade that version to the most recent LimeSurvey version. Check the page related to how an installation can be transferred for more details.