Some thinkings about the technological level of my setting:
General technology: 1920s with some early 30s, consider 1925 as an average, although the colonies in the northern continent may lag behind several decades.
Military technology: Firearms are pre-WW2 models, although semi-automatic rifles are more advanced and widespread than the OTL (conversely, no one is using or even thought up the submachine guns).
Naval battles are dominated by battleships, and although some navies are using aircraft as reconnaissance element nobody has even a plan for the carrier.
Technical development of aircraft has focused on long-range reconnaissance and close support of land force, but little advancements are made in matters of air-to-air combat and strategic bombing mission. Airships are fairly widespread in use, however, and utilized for observance, transportation, and bombing mission, albeit not very successful with the last.
Radar is non-existent, and everyone is just about grasping the potential of radio technology.
Due to the geographical and climatic reasons, cavalry was always the most important element in Underheavenite warfare and this translates into the enthusiastic adoption of the mechanization and motorization of the army units. Without the experience of the WW1-style trench warfare, tank developments are less concerned with breaking through the enemy lines and more with replacing the roles of traditional cavalry.
The main weapons for cavalrymen are a handgun on the horseback and carbine on the dismount. Sabers and other melee weapons are used, but most cavalrymen prefer to have an additional handgun rather than drawing the blade.