Here's something from Chicken's forum, I compiled this from a couple of posts by Simon-
What you're experiencing is a direct result of you crunching Beta as
well as the main project. Beta thinks 5.17 is the app you need, and
BOINC seemingly cannot distinguish between the Beta and the standard
app right now.
That's entirely normal -
I included an updated app_info.xml in
the 2.0 releases because there remain some problems with 5.4.x and
prior BOINC versions when you run both the Beta and the main project
for SETI. Thing is, if you do not include a 5.17 entry for those hosts,
they will just error out a lot of WUs and make people very unhappy

So
BOINC now thinking your app version being 5.17 and requesting WUs for
that version is normal, and quite okay. For the moment, the main
project does not send out any WUs that cannot be processed by 5.15 in
any case.
HTH,
Simon.
So are ya'll running Seti Beta, also?