I tried to upgrade Zerotier and I am not sure what needs to happen. Did it update?
root@GL-AX1800:~# opkg update
Downloading https://fw.gl-inet.com/releases/v21.02-SNAPSHOT/kmod-4.2.1/arm_cortex-a7/ip60xx/Packages.gz
Updated list of available packages in /var/opkg-lists/glinet_core
Downloading https://fw.gl-inet.com/releases/v21.02-SNAPSHOT/packages-4.1/arm_cortex-a7/glinet/Packages.gz
Updated list of available packages in /var/opkg-lists/glinet_gli_pub
Downloading https://fw.gl-inet.com/releases/v21.02-SNAPSHOT/packages-4.0/arm_cortex-a7/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/opnwrt_packages
Updating database.
Database update completed.
root@GL-AX1800:~# opkg upgrade zerotier
Upgrading zerotier on root from 1.8.4-1 to 1.8.4-2...
Downloading https://fw.gl-inet.com/releases/v21.02-SNAPSHOT/packages-4.0/arm_cortex-a7/packages/zerotier_1.8.4-2_arm_cortex-a7.ipk
Existing conffile /etc/config/zerotier is different from the conffile in the new package. The new conffile will be placed at /etc/config/zerotier-opkg.
Configuring zerotier.
disabled in config