diff --git a/CHANGELOG.md b/CHANGELOG.md
index 311be72099307eb4dda80574688ef8550d4ede19..3a2c07e6f7bb8f899aa4bf101cf3497510ff71dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ Differences Between DuMu<sup>x</sup> 3.3 and DuMu<sup>x</sup> 3.2
   and might undergo unannounced API changes until further notice. This concerns the files in the folders `python` and `dumux/python`. To activate
     - add `-DDUNE_ENABLE_PYTHONBINDINGS=TRUE` and `-DCMAKE_POSITION_INDEPENDENT_CODE=TRUE` to your CMAKE_FLAGS and run dunecontrol
     - run `python3 dune-common/bin/setup_dunepy.py`
+- We now include a basic version of the [fmt-library](https://github.com/fmtlib/fmt) which implements `std::format` (coming with C++20) with the need for C++20.
+  In order to use this, include `<dumux/io/format.hh>`. `format`, `format_to`, `format_to_n`, `formatted_size` are available in the `Dumux::Fmt` namespace.
+  The string formatting is documented [here](https://en.cppreference.com/w/cpp/utility/format/formatter#Standard_format_specification) and follows the Python string formatting rules.
+  The function are documented on [cppreference](https://en.cppreference.com/w/cpp/utility/format).
 
 ### Immediate interface changes not allowing/requiring a deprecation period: