Theano will not be maintained after the 1.0 release, announced by the MILA group.
Theano is a Python library that allows to define, optimize, and evaluate mathematical expressions involving multi-dimensional arrays efficiently. Especially, many people have started their Deep Learning research and implementation with Theano, which has been one of the most well-known frameworks as Caffe and Tensorflow. It has been almost ten years of use and development of Theano. The MILA group mentioned that Theano can still continue to be available, minimal maintenance to keep it working for one year, but there will be no update for new features.