For page change events simply place the sendme command into the initialization for each page. Then as soon as a page is loaded the display will send the new page number down to the photon. The photon will capture the event, call your registered function, and then you can load the data for that page. This is much better than having to continually request the page number and wait for it to change.
Also, I have been trying to ensure I update with nextion’s changes.
It's a pain that Nextion doesn't seem to accept any PRs on their repo (I once tried a minimal Particle "update", but it just got dumped).
So I hope it won't become too tedious for you to keep your port updated whenever they decide to change something.
