…and if so, to what, and roughly by when? More threads is a good use for dollars, at least up to 16 or so. More megahertz is basically a negative value, since it sacrifices battery life in exchange for trivial performance improvements just to satisfy the benchmark nerds – unless it’s on a totally different silicon process that can deliver more for the same power budget.
I guess it will be after shipping of L14, now it is too late to adapt the CPU of Librem Mini to L15 if you can get a better one in three months.
I have no inside information but I would think that, if Librem 15v5 comes into being, it is near certain that it will be a CPU upgrade over the Librem 15v4. I would expect a CPU at least as good as the one in the Librem 14.
The Librem 15 v5 is likely to have the same 6-core CPU used in the Librem 14. As I explained in this post, not launching the Librem 15 v5 was probably a cost saving measure, but I expect Purism to launch it once it has the cash on hand to pay for the costs of a new model.