#1768 changelog

Author: valentinsulzer

CHANGELOG.md

@@ -2,9 +2,12 @@
 
 ## Bug fixes
 
--   Fixed finite volume discretization in spherical polar coordinates ([#1782](https://github.com/pybamm-team/PyBaMM/pull/1782))
 -   Fixed `sympy` operators for `Arctan` and `Exponential` ([#1786](https://github.com/pybamm-team/PyBaMM/pull/1786))
+-   Fixed finite volume discretization in spherical polar coordinates ([#1782](https://github.com/pybamm-team/PyBaMM/pull/1782))
+
+## Breaking changes
 
+-   Raise error if `Concatenation` is used directly with `Variable` objects (`concatenation` should be used instead) ([#1789](https://github.com/pybamm-team/PyBaMM/pull/1789))
 # [v21.10](https://github.com/pybamm-team/PyBaMM/tree/v21.9) - 2021-10-31
 
 ## Features