Trilinos releases quarterly during the first month of each calendar quarter. The tentative schedule for major releases is below. Release updates occur as necessary (e.g. release 10.2.3 containing fixes for bugs in 10.2.2).
2016 Trilinos release schedule
February 3, 2016: Trilinos 12.6 (repository freeze January 12)
July 27, 2016: Trilinos 12.8 (repository freeze July 12)
November 16, 2016: Trilinos 12.10 (repository freeze November 1)