Hello.
I have been using this mobile router for three years and recently I noticed that the internet speed is very slow even though the maximum supported download and upload speed is 150 mbps.
Do you know any solution to restore the old speed?
In the past . My download speed was between 50-60mbps and now I can download files very slowly.

Maybe the firmware needs to be updated. I suppose you've tried resetting it by unplugging it for thirty seconds and then plugging it back in? I'm sure more things can be tried but I don't have the technical knowledge to recommend such options.

I checked for firmware updates, but the current firmware is up to date.

Sorry, I can't answer your question but I hope it got solved. I'm searching for a mobile router though and wondered, is this one accessible/ccan you recommend it or another router?

Its application is available, but the router itself is not. It can only be controlled from the telephone application or from the web interface.