diff --git a/cura/Utils/Decorators.py b/cura/Utils/Decorators.py
index 3f652234d5..52f61eb1f5 100644
--- a/cura/Utils/Decorators.py
+++ b/cura/Utils/Decorators.py
@@ -2,15 +2,25 @@
 # Cura is released under the terms of the LGPLv3 or higher.
 
 import functools
+import re
+
+# An API version must be a semantic version "x.y.z" where ".z" is optional. So the valid formats are as follows:
+#  - x.y.z
+#  - x.y
+SEMANTIC_VERSION_REGEX = re.compile(r"^[0-9]+\.[0-9]+(\.[0-9]+)?$")
 
 
 ##  Decorator for functions that belong to a set of APIs. For now, this should only be used for officially supported
 #   APIs, meaning that those APIs should be versioned and maintained.
 #
-#   \param since The earliest version since when this API becomes supported. This means that since this version, this
-#                API function is supposed to behave the same. This parameter is not used. It's just a documentation.
-#
-def api(since = "Unknown"):
+#   \param since_version The earliest version since when this API becomes supported. This means that since this version,
+#                        this API function is supposed to behave the same. This parameter is not used. It's just a
+#                        documentation.
+def api(since_version: str) -> callable:
+    # Make sure that APi versions are semantic versions
+    if not SEMANTIC_VERSION_REGEX.fullmatch(since_version):
+        raise ValueError("API since_version [%s] is not a semantic version." % since_version)
+
     def api_decorator(function):
         @functools.wraps(function)
         def api_wrapper(*args, **kwargs):