Fortinet AP - Life Cycle

HI All, I have some Forti-APs 221C. They are supported until 2023. I noticed there was an vulnerability noted and Fortinet recommended upgrading the firmware on APs. They are telling me they no longer providing firmware for this model. So I am a little confused. How do you know what Fortinet is going to stop providing firmware? Other vendors I have worked with it has been based on the end of support date, but they are tell me no. This AP is only 3 years old. Not really that old.