... and is on its way to the mirrors (my own mirror got it already).
Debian Trixie is now 'Stable', Bookworm is 'Oldstable'.
Trixie includes FLTK 1.4.3 whereas FLTK 1.4.4 has already
been adopted by several other distributions (as of now: 39 according
to repology, although this includes duplicate counts for 'Arch'
etc.). [1]
As far as I understood Trixie will most likely stay on 1.4.3
(because it's "stable") but may get patches during its lifetime if
necessary.
--------
[1]
https://repology.org/project/fltk/versions