Star Trek: Theurgy Canon

Quantum reality, or quantum universe, was the term used to describe the alternate timelines in which all possible outcomes for any event take place. Each quantum reality was its own separate parallel universe characterized by a unique quantum signature which could not be altered. All matter resonated on a quantum level with this signature within the universes. In the Theurgy reality, as a result of different events and actions, there were differences from the normal state of the universe as of the year 2381.

Comparing it to the reality where the USS Enterprise fought the Reman Praetor Schinzon in 2379, these were the differences in the Theurgy universe:

Starfleet Command

The alien neural parasites that infiltrated Starfleet Command in the year 2364 never did so (TNG, Episode 1x25 "Conspiracy"). Instead, the enigmatic aliens in the Theurgy timeline did, but at a later time. The nature of these other aliens were shrouded in mystery, but they were not so easily detected. They existed in a state of flux, and affected the host differently. The goals of these aliens were not fully explored, but it was evident that they were of chaotic origin.

No Slipstream Drives

After the USS Voyager returned to Federation space in the year 2378, despite many attempts, neither Starfleet nor any other faction in the galaxy was able to re-create the Quantum Slipstream Drive that Species 116 showed to the crew of the Voyager. Furthermore, Transphasic Torpedoes have yet to be put in mass production, still being in early testing stages, just like Transphasic Shielding or Transphasic Compression Phaser Cannons. However, when the USS Calamity was sent back in time to hunt down the Theurgy and the Harbinger, the AC-507 Mk I Reaver Warp Fighters were fitted with this kind of weaponry, and the Calamity had similar weaponry.

Starship Development

After Starfleet Command was overtaken by the aliens in the Theurgy universe, they began to mobilise its fleet earlier. A lot of resources were put into the fleet yards around the Alpha Quadrant, and the Advanced Starship Design Bureau got everything they needed in order to launch new starships at a quicker pace.

For example, the Theurgy Project was finished in 2378, its first prototype ship - the USS Theurgy - launched thee years ahead of schedule. Also, the Odyssey-class line of starships were launched in 2380, with three ships leaving the fleet yards simultaneously. These were the USS Odyssey NX-74699, under the command of Admiral Janeway, the USS Entreprise NCC-1701-F - replacing the Sovreign-class NCC-1701-E, under the command of Captain Picard and the USS Archeron NCC-74700, under the command of Admiral Sankolov.

Starfleet Aerospace Command Division

The formation of Starfleet Aerospace Command was heavily influenced by the successful deployment of Peregrine-class fighters aboard the starships serving as carriers in the fleet, which was successfully deployed in the Dominion War. The Tactical CONN department belonged to this Division, and its officers consisted of fighter pilots with the white-collared uniform.

The year 2375 - after the conclusion of the Dominion War - the AC-205 Mk I Valkyrie line of fighters were launched, followed by the Mk II and Mk III in 2376 and 2378 respectively. Besides the Valkyrie-program, a competitive Interceptor-program was also implemented, resulting in the AC-347 Knight-class Interceptor being commissioned to starbases and planetary outposts throughout the Federation in 2377. This focus on developing fighter-based crafts for Starfleet was also a shift from Starfleet Command, suggesting that the alien usurpers could have been present as early as 2375, or at least some point after that.