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@@ -34,8 +34,8 @@ Original authors: Campbell Barton, Bart, Bastien Montagne, Seva Alekseyev
 ## Specifications
 For deeper understanding of both file formats supported by this extension, refer to:
 - [VRML (.wrl)](https://graphcomp.com/info/specs/sgi/vrml/)
-- [X3D (.x3d)](https://www.web3d.org/specifications/) and [X3D V3.3(.x3d)](https://www.web3d.org/documents/specifications/19775-1/V3.3/index.html)
+- [X3D (.x3d)](https://www.web3d.org/specifications/) and [X3D V4.0(.x3d)](https://www.web3d.org/documents/specifications/19775-1/V4.0/index.html)
 
 Comparison software:
 - [FreeWRL](https://freewrl.sourceforge.io/)
-- [x3dom](https://www.x3dom.org/)
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+- [x3dom](https://www.x3dom.org/)