Fix config URL so that the phones don't get an invalid URL when $domain_name is unset. They would previously receive `/app/provision` with no domain/ip included, which makes the phone unable to provision again once they have been added to the Devices page without manually re-setting the config URL or factory defaulting the device.
The alternative solution is that the PHP code could always ensure that the $domain_name variable is set even if the device doesn't exist. My suggestion is to see if it can be set to the same domain/IP as the original provision request from this unconfigured device
Excludes the P8352 value if the default setting grandstream_speaker_ring_volume is unset. Depends on PR #5522
Before anyone asks, Mandatory just means that the variable must be valid, not that it must be included in every XML download. The phone already has a valid value in its internal settings, so as long as we stay safe from setting it to an empty value or outside of the range of 0-7, we are safe. Excluding it is a valid option, which is also true for all settings labelled Mandatory in the Grandstream templates.
Enable the option to prevent incoming calls from interrupting outbound dialing (a commonly requested functionality)
Enable the option to bypass Grandstream phone's dialplan when dialing from call history (to prevent errors on calls that contained a + in front of them)
P2916 (wallpaper source) is defined twice in the file: once statically and then again immediately after in an if/else statement. The latter is correct. Having it defined twice causes the phone to ignore the second declaration.
* Added the ability to pick the SIP account for the first two slots on each handset
* Revert to clean base
* Configurable firmware versions for the Grandstream DP750
* GXP2170 Config File improvements
* Added OpenVPN options back (but commented out), changed call waiting & vlan variables
* Readd Broadsoft Features, but commented out