Regarding the NOTAM briefing, you'll see a big red warning at the top of the NOTAM tab if your NOTAM data is out of date by 30 minutes or more. That's the best way of ascertaining whether it's been updated during flight.

Hi Tim,
thank you for your response. I know that there is a tiny part of the wifi icon on top of the Android screen indicating offline by a '!' and online by two very tiny up/down arrows but this is hard to identify while flying and does not provide information whether SD did receive new data or not. I think the main interesting things while flying are weather and NOTAM update status. TAF and METAR provide their update time as part of the regular data but NOTAM does not. I could imagine a little colored label on top of the NOTAM (and weather) tab/s with information (date/time) when the last update was received from the web since SD was started. Color could indicate red:no update, yellow:partially updated, green completely update. Of course this is not a thing of high priority and I know that this in fact belongs to the section 'Suggestions and Beta Discussions'. So feel free to move it to there ;-)

There's lots of different briefing information that SkyDemon attempts to update periodically when it's advised there is an internet connection available by your device. SkyDemon doesn't tell you anywhere that all the different information has been updated, but your device should tell you on its screen if it's using either wifi or 3/4/5g to access the internet.

SD Version 3.16.3.21673 on Android.
I am using SD with a device that is able to provide GPS/traffic data and working as a mobile internet router at the same time. Due to the unreliable mobile connection during flight the router-part of the device is only online now and then.
Thanks for some more detailed information about the related mechanism behind the SD scenes.