Yes, RERA can apply to old projects, but it depends on the project's status and when it was completed.
Under the Real Estate (Regulation and Development) Act, 2016, projects that were ongoing when RERA came into force on May 1, 2017, and had not received a completion certificate, generally had to be registered with the relevant State RERA authority.
However, a project that had already received its completion certificate before May 1, 2017 is generally not required to be registered under RERA.
For an old project, you should therefore check:
When the project was launched.
Whether construction was ongoing on May 1, 2017.
Whether a completion or occupancy certificate had been issued before that date.
Whether the project was registered with the applicable State RERA authority.
Whether your dispute concerns an act or obligation that falls within RERA's jurisdiction.
Also, RERA does not automatically exclude older disputes simply because the project is old. The specific facts, the State RERA rules, and the nature of the complaint matter.