Major Changes

Backwards compatibility breaks and deprecations

• lambdify now uses modules='numpy' by default if NumPy is installed. Previously it used modules=['math', 'numpy', 'mpmath', 'sympy']. It still uses modules=['math', 'mpmath', 'sympy'] if NumPy is not installed, although this may change in a future version. If you relied on the old behavior of mixing NumPy and non-NumPy functions, you should explicitly pass the modules argument of lambdify (the third argument). (#11468)
• as_finite_diff is now deprecated. Users are encouraged to use Derivative.as_finite_difference instead. A new helper function called differentiate_finite helps the user to differentiate an expression and replace Derivative instances with finite difference approximations.

New features

• Tensorflow support in lambdify (#11439)
• ReferenceFrame.orient() accepts rotation matrices manually (#11552)
• Solutions to radical equations that return a ComplementSet no longer raise an error and solutions to the same which cannot be affirmatively verified to be solutions are returned in a ConditionSet (#11537)
• SymEngine can be used as the symbolic core in sympy.physics.mechanics by setting the environment variable USE_SYMENGINE=1. (#11002)

Minor changes