The developers announced in July 2015 with beta 15f2 that they had finished adding new features, and that any future releases would only correct bugs or balance issues.

It was first uploaded to NexusMods on 4 January 2013, and exited beta with the release of version 1.0 on 28 December 2015. Long War is a partial conversion mod for XCOM: Enemy Unknown and XCOM: Enemy Within. Enemy Within added two additional ways for players to upgrade their soldiers - through genetic modification and through cybernetic combat suits called MECs - as well as new alien units and a new enemy faction, a secret paramilitary organization called EXALT. XCOM: Enemy Within is an expansion of Enemy Unknown, and was released in November 2013. The player directs the organization's research and development, manages its finances, and controls its soldiers in combat.

In XCOM: Enemy Unknown, the player assumes the role of the commander of a secret multinational military organization, XCOM, as it fights off an invasion by a numerically and technologically superior invading alien force. XCOM: Enemy Unknown is a turn-based tactics video game developed by Firaxis Games and released in October 2012. On 19 January 2017, the core team that released Long War, now going by the name Pavonis Interactive, released Long War 2 for XCOM 2. Firaxis pointed to the popularity of Long War as a reason they added built-in support for modding into the sequel XCOM 2, and used Long War Studios to provide initial add-ons for the game at release. It has been downloaded over 1,000,000 times, by almost 400,000 different users. Long War has received praise from both video game journalists and from the developers at Firaxis. By the end of the mod's development, the team was working directly with the Unreal Development Kit and had created a Java-based tool to help manage the changes that the mod was making. According to one of the mod's core developers, Amineri, the mod started as a series of changes to the base game's configuration file, and grew more expansive as the team's capabilities grew. The mod was developed by Long War Studios, a team that came to include four core members, with assistance from 29 contributors, 20 voice actors, and three members of Firaxis Games, the developer of Enemy Unknown and Enemy Within. Long War adds a significant number of new soldier classes, abilities, weapons, armors, and usable items, and also introduces new features, including soldier fatigue and improvements to alien units over the course of the game. Almost every aspect of the original game is altered, creating a longer, more complex campaign that presents players with more strategic choices and customization options. It was first released in early 2013, and it exited beta at the end of 2015. Long War is a fan-made partial conversion mod for the turn-based tactics video game XCOM: Enemy Unknown and its expansion, XCOM: Enemy Within.

War of the chosen mods