I downloaded the updated zerotier package to the tmp folder on the router and tried installing but get:

Upgrading zerotier on root from 1.2.8-2 to 1.4.6-1…
Collected errors:

  • satisfy_dependencies_for: Cannot satisfy the following dependencies for zerotier:
  •  libstdcpp6
    
  • opkg_install_cmd: Cannot install package zerotier.
    root@GL-MT300N-V2:/tmp# opkg install libstdcpp6
    Unknown package ‘libstdcpp6’.
    Collected errors:
  • opkg_install_cmd: Cannot install package libstdcpp6.