hi it is possible to upgrade from LEDE 17.01.7 to openwrt 19.07.3 through the page using the file sysupgrade.bin without problems
Generally speaking, yes you can. Make sure:
- the router can be flashed with 19.07.3 , that means it has enough flash space, RAM, and CPU.
- you take a backup
- use sysupgrade image
- when you upgrade don't keep settings
- restore manually the settings, not from Luci restore.
- use opkgscript to take a backup of your installed packets and reinstall them after flashing.
That a set of really useful tools. Thanks for pointing to it.