While Criminal Girls X has been announced to be released as both a free-to-play game and a pay-once version, Mikage LLC has revealed that the pay-once version will be released via crowdfunding via Campfire.
Originally, while the Criminal Girls series was released on portable game devices, due to the end of production for those devices, Criminal Girls X was decided to be smartphone/PC as they were the most prolific devices. The game became a social/free-to-play game style because of observations that RPGs on the App Store either ports, or released with extra downloads/DLC in mind.
According to the Campfire page, Mikage was then inspired by comments on Twitter which left a great impression on him – once these sort of social games are shut down, nothing remains. Yet, a pay-once version would need to be fundamentally different from what has been created for the current versions. So he turned to crowdfunding in order to see what demand was like.
The crowdfunding campaign has not begun, but more details and screenshots will be released over the course of this month. You can find the page here.
Criminal Girls X is currently in development for PCs and both Android and Apple iOS devices in Japan. A possible western PS4 release may occur.