Reactivating System License on 3600 series

The reactivation of the license will only cause brief traffic disruption (therefore we usually reactivate on a standby node) but you will not hit a wall until you attempt to upgrade.

The consideration to have when you upgrade concerns your support contract and the license date embedded in each image version.

Use this document to ascertain the license check date for the desired release. This would be 2016-03-18 for the 12.1.2 release you mentioned.

https://support.f5.com/csp/article/K7727

Your service check date which is determined by your support contract must have a value of 2016-03-18 or later in order for you to upgrade to 12.1.2. In other words, you must have had an active contract on the date the version was released.

When you reactivate your license, the expiration of your support contract will be updated as the value for your licenses service check date.