What worked for me (and may or may not work for you) to get some useful results: the paper required very short exposure compared to new Ilford paper (about 1 stop less), but it required a loooong development time. Where I normally see some image appear after, what, 10-20 seconds(?), it takes a full minute for this Brovira. After some trial and error, it seems that after that, it still requires about 90 seconds, so total would be 2 1/2 minute.
Comparing my last print of this evening to the first attempts, I'd say with some adjustments the paper is still useable. But I have to check tomorrow in daylight to be sure.
Regardless of that: wow, my darkroom / our bathroom smells better than ever. The lovely smell of old Brovira, mmmm! (So, in the event that it turns out to be unuseable for any serious printing, I will take out one paper every now and then just to smell it... )
All I can say is: do some testing. Don't give up too soon, try different things (took me a few prints to figure out; I'm glad I was persistent enough). Good luck!