I cannot contribute with experiences but I can help with the release dates (from the FTP server):

  NW 8.0.4.4          07/23/2015

  NW 8.1.2.1          11/06/2014      (so 8.1.2.0 must have been release 1..2 months earlier)

8.0.4.5 should be release now to address recent ETA, but I doubt they updated DDBoost library there - remains to be seen.  Of course, one could try to use newer ddboost lib, but then again it is not tested against NW code so this would be kind of risk.  Same thing is keeping away me from applying DDOS 5.5 on DDs where I have NSR still using 8.0.4.x on server.

Interesting enough, though not directly applicable to you, one of my colleagues updated two DDs from 5.4.4.2 to .5.5.2.2. These DDs also contained 2 to be decommissioned datazones based on oldish 7.6.5.7 and needless to say all DDBoost devices didn't work after that (File handle is stale errors).  So, it might be that the same destiny awaits those who would try the same with 8.0.4.x.  Better stay away.

I've also read somewhere about 8.0.4.5 - but this version doesn't exists on the ftp site yet.

(I'm sooo unlucky with NW releases.. once I deployed the withdrawn version of NW - now I've asked my customers to deploy 8.0.4.4 - right before 8.0.4.5 will be released )

I didn't wanted to replace the ddboost lib - 2.6.3.0 is used by NW8SP4 by default. That's why I hope that it will work with DDOS 5.5.

But it's really bad news (to me) that it's not in use on your sites..

I've opened an SR which is now forwarded to the NetWorker Engineering Team because the documentations may contain contradictory information. I'll let you know the results.

I think it's really sick that EMC is not trying to keep the backward compatibility of their products.

I can understand that they "can't" support backup clients if eg. the O/S vendor support is expired (eg. win2003), but NW8.0 is supported until 31/03/2016..so DDOS should also support it - or the fixed DDOS bugs should be backported to supported versions.

We had a ddfs restart issue a few days ago - the root cause of this is fixed in DDOS 5.5.3.1..so this event also asks for an upgrade, but now it seems that we can't do it..

(we have some good old AIX 5.3 systems.. they are officially not supported by NW8.0, but NW was running well there.. however it's not possible to install NW8.1, some libraries are really outdated. So if nw8sp4 won't support ddos 5.5 then we have to stay on 5.4 for a while.. or disabling client direct may be our last remedy??))

I've got the official statement from EMC support: you were right, NW 8.0.4.4 is not compatible with DDOS 5.5.x

The only way to backup an old system running NW8.0.x to a DD which runs DDOS 5.5+ is to disable client direct..

bingo, Hrvoje, thx for the replies.

I'm not sure which DDOS you run before, but 5.4.4.2 for me was super stable (and still is for some systems).  I do not see the reason to rush.  You have ddboost compatibility matrix so you can easily make decision on upgrade path.