Based discussions by Antonio and others in July 2018 on this thread:
...the proposal is to have a NetBeans release 4 times per year:
2018
- August 2018
- JDK 9 and 10 support
- JDK 9 and 10 support
- November 2018
2019
- February 2019
- May 2019
- August 2019
- November 2019
2020
- February 2020
- May 2020
- August 2020
- November 2020