For anyone wondering about the status of this Visual Novel, I'm here to tell you some information.
Yes, the development of this is still in hiatus. The developer is currently finishing up the last major content update for one of the character routes in their other Visual Novel, Repeat. (Although it should be noted that it will likely come out first for patrons of their Patreon, and non-subscribers will be an update behind in comparison.)
However, let it be known, that the moment the update for Repeat is completed, Shirokoi plans to resume their work on Temptations Ballad. They have many things in store for us.
Don't worry, development is NOT dead, just on hold, and it will pick up once their current project is finished. For now, if you're still antsy from waiting, try reading Repeat. It is also a great Visual Novel to enjoy.
I hope this set you at ease.