The main thing about this release is that only 6.2.6 and later are not vulnerable to this:[link]https://www.fortiguard.com/psirt/FG-IR-20-068[/link]
but 6.2.6 has this ipsec issue:
FortiOS 6.2.6 IKE process crash2020-11-25
Subject: FortiOS 6.2.6 IKE process crash
Upon upgrading to FortiOS 6.2.6, a device with IPsec configured may experience IKE process crashes when any configuration change is made or an address change occur on a dynamic interface.
Potentially Affected Products:
Potentially Affected OS:
Use software version 6.2.5 until FortiOS 6.2.7 is available
Fortinet has resolved the issue in the upcoming FortiOS 6.2.7.
Contact Fortinet Technical Support to request a 6.2.6 special build hot fix for an interim solution for
use until FortiOS 6.2.7 is available.
So upgrading to 6.2.7 would solve both situations.