Not to drive you completely nuts ['though I've been accused of having that propensity ] so consider the following as 'For Your Information'; somethings you might want to consider before making your Final Remaster.
The reason there are so many Puppys is that by definition Puppys (other than Remasters) are created using an application known as 'woof'. Woof makes use of the binaries of a Major Linux Disto Version, and builds into the Puppy being 'woofed' direct access that Distro Version's repositories. In theory, any Distro can be used. In practice, the Distros woofed have mainly been Slackware, debian, Ubuntu and recently Void.
Puppy is not a 'rolling release'. To update it entirely, one has to either woof a new version, or remaster the old version. With the exception of the core/foundation glibc libraries, pretty much everything else can be updated without having to woof a new version. An operating system can only have one glibc version: many of its applications may break if you change it. And even a woofed new version can not include a new glibc unless the 'Source' Distro updated the glibc. [But there are techniques for building applications with other glibc versions]. So, when debian, Ubuntu or Slackware publishes a new OS, it's not uncommon for some Puppy Dev to woof a new Puppy binary compatible to it, and publish that new version. This often results in other Puppy Fans eventually creating remasters of that Puppy.
666philb published Fossapup64_9.5 on Sep 20, 2020, woofed from the Ubuntu focal fossa of April 20,2020 and such 'bug-fixes' as Ubuntu may have published by then. It’s not uncommon after a Puppy’s initial release for its Dev to respond to suggestions, and especially calls for ‘bug-fixes’. I don’t recall, but perhaps 666philb did that. However, 666philb has not been active on the Forum for the last couple of years. So it’s best to consider Fossapup64_9.5 as having been ‘locked’ around September 20, 2020; and that includes the applications which it provides if you use Menu>Setup>Quickpet.
Puppy Devs/Fans have continued to publish newer application and newer versions of application which Fossapup64_9.5 can use. Generally, you’ll find them in the Additional Software Section, viewforum.php?f=7. The OP of each Thread will usually identify which Puppys the App being discussed will function under. ‘No-Arch’ applications can almost always be used in any Puppy. But I want to make certain you are aware of a couple Sections of the Forum particularly significant for Fossapup64_9.5, and why.
I generally follow the advice “If it ain’t broke, don’t fix it.” But when I do a remaster, I want to update as much as possible anything relating to Security, accessing the Web, and the convenience in User Customization. You’ll find rerwin’s latest network managers here, viewtopic.php?p=2241#p2241. You’ll find radky’s latest JWM-Desk here, viewtopic.php?p=32274#p32274. A link from that post will lead you to radky’s other ‘PupMates’ here, https://www.smokey01.com/radky/PupMates.html. That Webpage shows the last publication date of application.
There have been many new applications specifically created for Fossapup64. You’ll find them in this Section, viewtopic.php?t=1239. Ones I think especially worth considering are jasper’s applications having to do with accessing the web, including Openssl. I suggest scanning that entire Section; but I think Jasper’s contributions begin here viewtopic.php?p=73987#p73987. Perhaps scan backwards from the end as I noticed some updates to his earlier updates.
Recently, ozsouth has published a series of Fossapup64 Remasters. You’ll find them on this Section, viewforum.php?f=119. Fossa-Mid is, I believe, the last ‘fleshed-out’ OS. It has built-in many of the new versions of applications ozsouth then compiled. That page has a list. But if you don’t want to ‘start from scratch’ by using Fossa-Mid, scanning thru ozsouth’s ‘closed’ thread will reveal links from which applications ozsouth and others created can be downloaded; such as those from here, viewtopic.php?p=92892#p92892.
As always, if you incorporate an application not specifically built for your Puppy (and Fossa-Mid is not identical to Fossapup64_9.5) always test before making that application a permanent part of your Puppy.
TBH, if you have the time and inclination, I’d recommend using Fossa-Mid for your project; or wizard’s Friendly-Fossa, viewtopic.php?p=43902#p43902 updated with applications from ozsouth’s Thread and the Fossapup User Contributed Packages Section. Sorry I didn’t think of that earlier.