diff --git a/GUIDELINES.md b/GUIDELINES.md
index 5a04dd7a73d6a4211f3039d124e8a2f47a2ba8e5..1bda00ff5c0774826b7d63c04d9aa59f15cc2cec 100644
--- a/GUIDELINES.md
+++ b/GUIDELINES.md
@@ -66,9 +66,7 @@ While `clang-format` does the structural formatting, we still need to agree on n
 
   - Code may not introduce any compiler errors, or warnings
   - All unit tests must succeed at all times
-  - We use C++14 concepts wherever possible
-    - Class members are initialized at definition
-    - we use "= delete", "= default", etc. identifier in class functions
+  - We use C++17 concepts wherever useful and helpful
   - On any major error or malfunction we throw an exception. This is needed and required for complex physics and shower debugging.
   - We never catch exceptions for error handling, there might be very few special exceptions from this. We need to discuss such cases.
   - Everything that should not change should be `const`