To check the software version and, if necessary, install a different
version, perform these steps. We recommend that you install your target version
before you configure the firewall. Alternatively, you can perform an upgrade after
you are up and running, but upgrading, which preserves your configuration, may take
longer than using this procedure.
What Version Should I Run?
Cisco recommends running a Gold Star release indicated by a
gold star next to the release number on the software download page. You can also
refer to the release strategy described in https://www.cisco.com/c/en/us/products/collateral/security/firewalls/bulletin-c25-743178.html; for example, this bulletin describes
short-term release numbering (with the latest features), long-term release numbering
(maintenance releases and patches for a longer period of time), or extra long-term
release numbering (maintenance releases and patches for the longest period of time,
for government certification).