when does the next KDevelop-Version (Linux) come? What is the difference between Version 5.6.2 and 5.10…
Afaik KDevelop releases with KDE Gear. For the release schedule you can look here: Schedules - KDE Community Wiki
Also are you talking about the KDE release schedule or releases of you distro? For example on my distro the current version of KDevelop is Version 5.12.230801 (23.08.1) which seems to be newer than the versions you asked about.
Unfortunately I have not found a changelog. Can you tell me what you are looking for?