Comment # 4 on bug 1205863 from Fabian Vogt

(In reply to Michael Dluhosch from comment #3)
> I noticed the isse because we use in our application following symbol
> "QQuickFramebufferObject::Renderer::framebufferObject const" which causes
> the final binary to use the wrongly private tagged symbol 
> "QQuickFramebufferObject::Renderer::framebufferObject()
> const@@Qt_5.15.2_PRIVATE_API" This binary needs now to be recompiled with
> every new update to the qt5declarative package. 
> We currently have SP1 SP3 and SP4 systems, it would be nice if I could
> compile on SP1 and just use the binary everywhere. This bug makes it
> impossible so I tried to get it fixed so that we can at least use our SP4
> binary when SP5 arrives.

Unfortunately the patch would not make that any better for SP5. Qt on SP5 would
then provide "QQuickFramebufferObject::Renderer::framebufferObject() const"
without symbol version and still not work. This would only improve it for a
possible SP6+. Backporting the change to SP4 is also not possible because it
breaks ABI. There might be a way to provide both symbols in SP4, but it won't
be simple.

Currently it's not clear whether SP5 will even get a newer Qt version than SP4,
so ATM your build against SP4 will work on SP5 unchanged.