Note: If "61 7" referred to a specific older legacy build or a specific hardware variant, let me know and I can adjust the version numbers!
Notable issues and drawbacks
Many network operators avoid the newest firmware due to feature removals (e.g., Telnet/SSH hardening, removal of certain debugging tools) or performance regressions on older hardware. Version 6.1.7 represents a “goldilocks” build: stable, feature-rich, and widely field-tested. ubnt firmware 61 7 licensed download work