While some older firmware (like b12) lacked these, newer community-tracked versions in other regions (like Sweden) may support advanced cell locking to force the router onto a specific tower for better reliability.
Depending on your regional provider, the following versions are currently in circulation: Versions include V1.00(ACBJ.0)b15 Three Sweden (Tre): Users have reported versions like V1.00(ACDJ.0)b8_D0 Generic/Generic-Alternative: zyxel nr5103e firmware update 39link39 exclusive
If you share the of the .39 file you’ve seen, I can help verify whether it’s an official Zyxel release for your specific NR5103E variant (e.g., Three, Teltonika, unbranded). While some older firmware (like b12) lacked these,