Hi
The AP's upgrade their firmware from the Zone Director using FTP on port 21.
Please verify the version of code presently running on the AP's by connecting to the AP's via CLI/SSH - get version.
If the AP's are running unleashed code (200.x) or SCG code (1.x, 2.x, 3.x, 5,x) then you will need to first flash the AP's with the standalone version of code 10x.x (104.x version of code is the most reliable).
Here are some KBA articles that might help:
How to upgrade standalone AP through FTP or local option
Upgrading standalone AP through FTP or local option
https://support.ruckuswireless.com/articles/000001297
Standalone AP upgrade via CLI
This article gives you information on how to upgrade the standalone AP via CLI.
https://support.ruckuswireless.com/articles/000001551
I hope this information is helpful.
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