HC-110 update needed...

You will excuse me to bring up this subject (again I suppose) but since I've heard there's been new developments regarding HC-110 [wrong?] maybe it is worthwhile taking a second look.

I took a picture of the several HC-110 bottles used in the past until today, so that could help sorting out the formula changes along the years.

Bottle "A" is the good old HC-110 syrup. Even when its color turned into brown color it was still reliable. I miss this one a lot.

Bottle "B". Lifespan is different. For instance I have been using a film [ultrafine extreme 400] from a bulk roll. According to the massive chart, the time dev is 5 min at 20C. Along the months (!) I realized I had to add up time to get a decent result. This week I had to go as long as 10 minutes for the same film at the same temperature. I understood that the manufacturer modified the old HC-110 for environmental purpose... What's going on?

Bottle "C" [LegacyPro L110 liquid film dev]. Not used yet. No idea of its lifespan once the bottle is opened up. Any opinion on this one?

Of course, I will consider using Adox HC-110 new formula that follows the good old formula.

My bottle of Kodak HC-110 looks more like the C bottle. I have crystals in it and it's been expired since I bought it (liquidy version) but it still works normally. I've been using it for 3 years.

I recently went through a bottle of the LegacyPro (your bottle "C") within a month or so, and it worked fine...I have no info on long term longevity, other than the paper seal in the cap is crap....sorry.
I recently purchased a bottle of Adox's "Syrup 110".
I'm about half-way through the bottle.
It is the thick stuff, like the vintage Kodak stuff, and dissolves easily.
I love it, but the paper seal in the bottle cap is crap, too, however.
I have a partial bottle of original Kodak HC-110 from c.1984, which pre-dates your bottle "A"...it is very dark.
I plan on doing an A/B test with it versus the Adox "Syrup 110" soon to see if it is still good.
Hope this helps.

I have the square (OG) pints. HC-110 and HC-110 replenisher. Enough to submit to the NASA folks for analysis

God I love the smell of the original stuff. Also replenishment in hard rubber tanks is the preferred way to honour the gods of Rochester!

I would put my money on Adox. Hopefully the original recipe is still known!

ADOX makes and sells two different versions.
The more expensive one uses a more complex and expensive manufacturing process that is at least similar to the one Kodak started with. It is probably even more similar to the process employed by Tetenal when they took over manufacturing after Kodak stopped manufacturing directly, and started having most of their non-motion picture photo chemicals for them.
Of course Tetenal subsequently went bankrupt, leaving no one in the world making that classic version of HC-110. A replacement version was put in its place in or about 2019, but it no longer offered the extreme, and unintended longevity.
ADOX and Photo Systems, the current licensee and manufacturer of Kodak branded photo chemicals, also manufacture another, lower cost version of what was known as HC-110 which gives very similar results, but doesn't offer the extreme longevity. Both offer it under slightly different versions of the name.
By the way, the old version of HC-110 wasn't really designed to provide the longevity it ended up being famous for.

Adox took over part of Tetenal's portfolio, including the syrup for HC-110. So what they sell is the old syrup under the Kodak brand, made in Germany. At the same time, they also sell the newest, cheaper version - which is exactly the same as what is currently sold under the Kodak brand, and from the same manufacturer in the USA. In short, from Fotoimpex you can buy both the old and the new form of HC-110.