Fortigate 600C

Does anyone still running Fortigate 600C? I'm at 5.6.9 1673.  I would like to upgrade to 5.6.12 build 1701, see upgrade path below,

5.6.11 1700 5.6.12 1701

Do you run into any issue when upgrade to 5.6.11 1700 and to 5.6.12 1701?

Also 5.6.12 1701 is the latest version end of the support on Oct 2021.  Does fortiness make anymore ew firmware ?