Add extra warning

docs/various-roles/developers-guide/intro.md

@@ -262,6 +262,12 @@ Merging branches is not described here. It's generally best to run npm version a
 
 #### Update version numbers
 
+:::warning
+
+It's easy to forget to update the version nummer in different locations. Please read carefully what is written below.
+
+:::
+
 Update the version number in four `package.json`'s. The idea is to keep the version numbers of all repos the same. If you publish an update to NPM you have to raise the version number in four places:
 
 1. https://github.com/trustoverip/spec-up-t-starter-pack/blob/main/spec-up-t-starterpack/package.json#L3