The Final Episode.

Most likely, it’ll be some kind of “this is not the end” ending, implying that there will be more adventures in Equestria and beyond. We just won’t get to see them. Possibly with an indirect “now go out and find your own adventures/friends, audience” as the last friendship lesson.
 
I can see there being some kind of retirement, maybe Celestia, if only as an excuse for the characters to give a “thank you for going on this journey with us” speech to us, via the retiree. If they do, I really hope it’s more of a celebration than a sad occasion. More “we wish you well because love”, less that scene from Snoopy, Come Home.

@Background Pony #0A87  
Which would be perfect. Adobe is discontinuing Flash outright sometime in 2020, so it would be a perfect excuse to switch to ToonBoom.

@Background Pony #0A87  
I’m upset now

@Background Pony #2054  
hmm.

I will refuse to acknowledge the ending if it involves Twilight, Cadance and Flurry living forever while their loved ones grow up and die.

@Background Pony #2E83  
Seeing as this is a kid’s show I doubt they’ll kill of the main characters at the end, even by old age.  
What’s that gonna teach a 5-year old? “You and everyone you know are gonna die one day. Have fun with that kiddo!”

@Usagi-Zakura  
And today’s (un)lucky word is: Puppysmiles, the filly who couldn’t die because she didn’t know how.

@Usagi-Zakura  
Well, to be fair, that is a lesson everyone needs to learn eventually.

@Nightweaver20xx  
Yeah but usually not MLP’s target age group…  
They would probably get quite a few complains from angry parents if they did that.
 
It’d be one thing if Granny Smith died, as she’s already old and that could be a good lesson for kids to prepare them for the death of a grandparent or something.  
But killing of 5 of the main cast leaving the sixth alone isn’t something I would expect out of a kid’s show. Even Disney, who’s quite fond of killing characters left and right, wouldn’t go that far.

@Background Pony #2E83  
reminds me when Regular Show off Pops in final episode

@Background Pony #B305  
error: killed off pops

@Background Pony #B305  
Autocorrect?

@Background Pony #0A87  
Right. In. The. FEELS.

According to the Hasbro CEO, their budget has plans all the way up to season 9.