This is a maintenance release with bug fixes in the Subscriptions app. Upgrading your installation is quite easy. If you have installed Anahita via Composer then use the following command in the root of your installation to get the updates:
$ composer update
If you are using the Anahita master branch on Github, just use the following command in the root of your Anahita installation:
$ git pull
There are no database migrations in this release. If you encountered any issues, please start a topic on the Tribe Support group.
Here is the change log for the 4.3.6 release.