I think they are having enough issues ironing out the expression and articulation bugs in 27, that Note Performer isn’t even on the radar at the moment.

Got it. 

David, according to Noteperformer's information, sul ponticello is not one of the provided string techniques. Only sul tasto is available, regardless of the notation program in use. 

Ah ok. I missed that in their documentation. Thanks. Still, glissando support would be helpful for sure. Can always hope. 

NotePerformer does play back glissandi, but (at present, as with many articulations and expressions) only using the legacy document style with the legacy Maestro font.

MakeMusic has already announced an update in the works that will configure SMuFL fonts to activate articulations and expressions, and I imagine that version will work with NotePerformer as well.

https://www.finalemusic.com/blog/future-of-smufl-in-finale/ 

Actually, for Finale (not Sibelius), NP does not yet accommodate glissandi. I've tried. It's awful. They explain it on their site as 

But I also was not aware that there is currently an issue with all expressions etc if a SMuFL font is used. I'll make sure to not use anything but a legacy font for the time being, and good to learn that MM is on it. But I can attest that NotePerformer does not function with glissandi in Finale. It apparently is accommodated in Sibelius. Thanks.

I had checked with piano, and I admit the same notation on a violin does not provide the effect expected in that it does a piano-like diatonic slide rather than a chromatic slide from one not to the other. So it is not correct that NP doesn't do a glissando; it is that (as your screenshot says) it does not do it correctly.

If Sibelius can produce a true portamento/glissando, then the problem is not with NP but with Finale.

As far as that goes, Dorico does the same thing (and they are aware of it, and it's on their roadmap).

Personally, it's a distinction without much difference. One or two string glissandi play back ok, most of mine do not in that they delay or omit the subsequent note after the glissandi. Whatever. I think NP is clear that it is not playing it back correctly, consistently. To me, that's saying that it does not support it. There is no such warning for Sibelius. I know it doesn't work either (correctly at least) with Dorico. What I understand from Wallander is that MM is aware, but the fix was taking longer than expected and at this point it was very much unclear when (if) this would be ameliorated. I get that third-party compatibility is not always at the top of a development priority list, for very understandable reasons. All I'm asking is that it still at least be prioritized. Not a mission-critical thing, for sure. But for some of us, it would be very much desired and appreciated.

You can smear NP all you want, but Finale needs to make the technique possible, and it can't produce a true gliss in Garritan Violin sounds either.

Uh, I think you're unintentionally misunderstanding me. No one is "smearing" NP. Not at all. I thought I made it pretty clear, including in my last post, that the fix needs to be made in Finale. Not NP. 

If anything, I think you're harshing on MM a bit, TBH. I rarely have used glissandi in my compositions (mostly in some early 12-tone instrumental music that bears little resemblance to the minimalism I've been writing since the early 80's), but have done so twice now in two recent string quartets using the GPO 5 sound files, and honestly I think glissandi were done pretty well by the GPO sounds (GPO 5, not the built-in GPO sound files that come with Finale). Nothing is perfect, but I was quite satisfied with the results. NP just couldn't do it; it tended to omit the notes (not part of the glissandi) right after the end of the glissandi, and there were other issues as well.