Domoticz install Fatal Python error: drop_gil: GIL is not locked

Hi, Fresh install of Domoticz on Netgear Nighthawk X4S R7800: OpenWrt 19.07.2 r10947-65030d81f3 / LuCI openwrt-19.07 branch git-20.057.55219-13dd17f fails to start.

Running

/usr/bin/domoticz -noupdates -approot /home/domoticz/ -debugleve
l -syslog daemon -userdata /root/ -sslwww 0 -www 8080

returns

2020-03-29 19:36:57.232  Status: Domoticz V4.9700 (c)2012-2018 GizMoCuz
2020-03-29 19:36:57.232  Status: Build Hash: b97777b, Date: 2018-06-23 15:18:06
2020-03-29 19:36:57.233  Status: Startup Path: /home/domoticz/
domoticz: Domoticz is starting up....
domoticz: Domoticz running...
domoticz: PluginSystem: Started, Python version '3.7.6'.
2020-03-29 19:36:57.382  Status: PluginSystem: Started, Python version '3.7.6'.
domoticz: Active notification Subsystems: gcm, http (2/13)
2020-03-29 19:36:57.389  Active notification Subsystems: gcm, http (2/13)
domoticz: WebServer(HTTP) started on address: :: with port 8080
2020-03-29 19:36:57.390  Status: WebServer(HTTP) started on address: :: with por                                                                                                                                                             t 8080
domoticz: Proxymanager started.
2020-03-29 19:36:57.392  Status: Proxymanager started.
domoticz: Starting shared server on: :::6144
2020-03-29 19:36:57.393  Starting shared server on: :::6144
domoticz: RxQueue: queue worker started...
2020-03-29 19:36:57.394  Status: RxQueue: queue worker started...
domoticz: TCPServer: shared server started...
2020-03-29 19:36:57.394  Status: TCPServer: shared server started...
domoticz: EventSystem: reset all events...
2020-03-29 19:36:59.396  Status: EventSystem: reset all events...
domoticz: EventSystem: reset all device statuses...
2020-03-29 19:36:59.398  Status: EventSystem: reset all device statuses...
Fatal Python error: drop_gil: GIL is not locked

Current thread 0xb64b8d54 (most recent call first):
  File "<frozen importlib._bootstrap_external>", line 81 in _path_stat
  File "<frozen importlib._bootstrap_external>", line 87 in _path_is_mode_type
  File "<frozen importlib._bootstrap_external>", line 102 in _path_isdir
  File "<frozen importlib._bootstrap_external>", line 1447 in path_hook_for_File                                                                                                                                                             Finder
  File "<frozen importlib._bootstrap_external>", line 1197 in _path_hooks
  File "<frozen importlib._bootstrap_external>", line 1221 in _path_importer_cac                                                                                                                                                             he
  File "<frozen importlib._bootstrap_external>", line 1249 in _get_spec
  File "<frozen importlib._bootstrap_external>", line 1280 in find_spec
  File "<frozen importlib._bootstrap>", line 906 in _find_spec
  File "<frozen importlib._bootstrap>", line 963 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 983 in _find_and_load
Aborted

Domoticz forums suggest that the version of domoticz isn't compatible with >=Python 3.7.

I've spent a few hours trying to work out how to build the very recent Domoticz 2020.1 but, sadly, it's beyond me. If I could get this to work I can switch off another machine at home and save a few more watts. OpenWRT is already making life better in our house. Nice one!