Sorry if this is repeated… I thought I asked this before, but alas cannot find it: (or maybe I have asked, what happens if I switch from D&U back to E mode…)
I use Devices & Users mode all over the place (out of what I perceived a necessity at the time of installation);
How does the upgrade-to-FreePBX-13 process treat D&U configurations, when encountered?
@el_es The Upgrade to FreePBX 13 from FreePBX 12 will upgrade you without issue and you will not loose any of your D&U settings. It’s fully supported and will honor your current configuration.
Thanks,
same thanks to user +Samot on IRC 
somehow, when FreePBX 13 was released, I was looking about into upgrade process and some articles/posts at the time suggested D&U wasn’t supported any more in 13… glad it’s not the case
Device and User is not officially supported by FreePBX, and that hasn’t changed for several versions. New features and releases may not necessarily be tested against D&U configurations, and there is no guarantee that anything that works now will continue to work in future releases.
That said, the devs are responsive to issues filed by D&U users, and the project strives to maintain existing functionality where feasible. This was demonstrated a few days ago when a recent change to hints affected the ability of D&U users to direct dial an extension from the IVR. Once the issue was eventually identified, it was fixed within days.
Good to have an answer from you @lgaetz
But otherwise, I can actually switch from D&U to E mode, and the Devices will be converted to Extensions correctly ? Cause then, it makes it possible for me, to switch to pjsip and use the muli-registration feature of that, to convert to something that /is/ officially supported, after I upgrade to 13 ?