diff --git a/docs/lib2-t2d.md b/docs/lib2-t2d.md
index 3d8a63df..dc196eaf 100644
--- a/docs/lib2-t2d.md
+++ b/docs/lib2-t2d.md
@@ -2,7 +2,7 @@
 
 An implementation of Turtle Graphics with Fluent API. It moves on the xy plane. You can get the cooridinate `[x, y]` or `angle` of its current position. 
 
-**Since: 2.1**
+**Since:** 2.1
 
 ## Parameters
 
diff --git a/docs/lib2-t3d.md b/docs/lib2-t3d.md
index 20cdc444..2ae9782d 100644
--- a/docs/lib2-t3d.md
+++ b/docs/lib2-t3d.md
@@ -4,7 +4,7 @@ An implementation of 3D Turtle Graphics with Fluent API. When using the function
 
 For more details, please see [3D turtle graphics](https://openhome.cc/eGossip/OpenSCAD/3DTurtleGraphics.html). 
 
-**Since: 2.1**
+**Since:** 2.1
 
 ## Parameters