We have run 3700Ds for 10 years or so, then they announced a EOL. Our head honchos decided to go with Cisco FTD9300 as replacements. This is almost a year ago when the cutover happened. It has been pure pain from hell of performance bottleneck after performance bottleneck. Most, if not all the issues were being seen by TAC for the first time ever. It was God send when Forti decided to extend the EOL to 2027. In no time it was decided to get the 3700D suited up.. My joy..
I think you meant EOO(End of Order) 2022-04-16 for 3700D when you decided migrating it to Cisco. All Fortinet products generally have 5 year continuous support before EOS(End of Support) until 2027-04-16 in the 3700D case.
But it's less than 4 years from now so you better be prepared for the next move whatever your org decides.
The Fortinet Security Fabric brings together the concepts of convergence and consolidation to provide comprehensive cybersecurity protection for all users, devices, and applications and across all network edges.