Go to downloads section of your Sitefinity's account and choose Sitefinity 3.7 or older versions distribution. You should use the account from which you downloaded Sitefinity 3.x initially.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items