"spot on" -- English phrase meaning "exactly correct"
Save your config, upgrade to 18.06.02 (or reinstall 18.06.01), install any additional packages you need, confirm that it works
In general, do not run
opkg upgrade until ABI-compatibility checks are present in OpenWrt. Until those checks are present, installing an upgraded ROM and a self-consistent set of packages is highly recommended for most users. A specific exception for this would be, for example, direction from a trusted member of the OpenWrt development team, not just some user on the forums (This is an example, do not do this now!), "All users running v17 or later should upgrade dropbear to resolve security issues. Users of versions prior to v17 should upgrade to v18.06.02 or later." (This is an example, do not do this now!)