Sorry for the delay, you can install this pre-release of the date-time-adapter on your gateway. You will need to manually install it. Note as this is a manual install, you install at your own risk and I am not liable for any issues or data loss that arises from installing and using it. Note i have tested this for over 2 months and you should be able to install it without removing the existing datetime device or altering existing rules that use the Sunset or Sunrise events.
#Remove the existing date-time-adapter
#Copy the new package to your gateway
Download the package from the above Github link.
scp date-time-adapter-1.0.1.tgz firstname.lastname@example.org:/home/pi/.mozilla-iot/addons
OR ssh to your gateway, cd /home/pi/.mozilla-iot/addons and wget https://github.com/damooooooooooh/date-time-adapter/releases/download/1.0.1/date-time-adapter-1.0.1.tgz
#ssh to the gateway
tar -xvf date-time-adapter-1.0.1.tgz
mv package date-time-adapter
sudo systemctl restart mozilla-iot-gateway.service or sudo reboot
#configure the package
goto the Settings > Addons Page
Find DateTime Adapter Addon and Configure
Enable the DateTime Adapter Adapter
#Wait for it to build, can take about 5 mins then
Goto to Things page and Add the new DateTime Adapter
#Reinstall 1.0.0 version
You can returnto the release version 1.0.0 of the adapter by removing this one through the adapter add/remove page and then add back the 1.0.0 one.
Sample logs below of -30mins offset for Sunset
2020-01-23 16:12:10.427 INFO : date-time: date_device.py:169 INFO now:2020-01-23 16:12:10.424119+00:00 > next:2020-01-23 16:42:08.816134+00:00
2020-01-23 16:12:10.430 INFO : date-time: date_device.py:172 INFO New event sunset_offset
2020-01-23 16:42:10.722 INFO : date-time: date_device.py:169 INFO now:2020-01-23 16:42:10.718688+00:00 > next:2020-01-23 16:42:08.816134+00:00
2020-01-23 16:42:10.725 INFO : date-time: date_device.py:172 INFO New event sunset
2020-01-23 16:42:10.727 INFO : date-time: util.py:113 INFO CALC_SUNSET today.utc: 2020/1/23 16:42:11 sunset: 2020/1/24 16:44:05 sunset_local: 2020-01-24 16:44:05.394557+00:00