TensorFlow 2.x introduced several improvements and changes compared to TensorFlow 1.x. One significant difference is the eager execution mode in TensorFlow 2.x, which allows for immediate evaluation of operations. This makes the framework more intuitive and similar to Python's NumPy library. Additionally, TensorFlow 2.x integrates the Keras high-level API, making it the official high-level API for model development. The transition to TensorFlow 2.x is encouraged due to its improved usability and enhanced features.