https://community.meraki.com/t5/Full-Stack-Network-Wide/MERAKI-BACKUP-AND-RESTORE/m-p/10899#M275   Hope this helps. ... View more

The 26.x release train is supported so I would upgrade, you have 3 weeks to downgrade if you find any issues.   https://documentation.meraki.com/zGeneral_Administration/Firmware_Upgrades/Product_Firmware_Version_Restrictions ... View more

Thanks  ... View more