There's no migration script. You really should keep up-to-date, as the last two versions include security and fixes for issues like YouTube embeds.
You should start now on upgrading to 7.1.6 (first to 7.1.5). Then you'll be able to upgrade to 7.2. As always, make a backup before upgrading, even to a minor version.
You should start now on upgrading to 7.1.6 (first to 7.1.5). Then you'll be able to upgrade to 7.2. As always, make a backup before upgrading, even to a minor version.