# 2021 File Format & Compatibility with Older Versions **URL:** \ **Category:** SketchUp\ **Created:** [November 18, 2020, 11:50am UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780 "2020-11-18T11:50:15Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![PaulMcAlenan](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/paulmcalenan/32/211206_2.png) [@PaulMcAlenan](https://forums.sketchup.com/u/PaulMcAlenan)\ **Post date:** [November 18, 2020, 11:50am UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/1 "2020-11-18T11:50:15Z")
Both MasterSketchUp and RubySketch on YouTube suggest that the new file format _should_ enable a file created in 2021 and newer to be opened in older versions. Is this working now in the current 2021 release or do we have to wait? I’ve tried and it doesn’t seem to work ---
**Author:** ![Box](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/box/32/235164_2.png) [@Box](https://forums.sketchup.com/u/Box)\ **Post date:** [November 18, 2020, 11:51am UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/2 "2020-11-18T11:51:15Z")
Can you give a link to where they say this. ---
**Author:** ![PaulMcAlenan](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/paulmcalenan/32/211206_2.png) [@PaulMcAlenan](https://forums.sketchup.com/u/PaulMcAlenan)\ **Post date:** [November 18, 2020, 11:53am UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/3 "2020-11-18T11:53:52Z")
at 7:50 in [![](https://global.discourse-cdn.com/sketchup/original/3X/f/1/f15a1ff496c9a8602c52ea533270a7736e2876f2.jpeg "SketchUp 2021 Review") ](https://www.youtube.com/watch?v=tuTgmel-mp8) at 6:15 in [![](https://global.discourse-cdn.com/sketchup/original/3X/9/1/91a7b2434046aa6f822df8d470de0c438c4495fb.jpeg "SketchUp 2021 Review") ](https://www.youtube.com/watch?v=I1lMs-GPnfs) ---
**Author:** ![Box](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/box/32/235164_2.png) [@Box](https://forums.sketchup.com/u/Box)\ **Post date:** [November 18, 2020, 12:01pm UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/4 "2020-11-18T12:01:05Z")
Well, Matt says ‘Hopefully this will allow…’ suggesting future. I know no more on the subject, but I’m skeptical. ---
**Author:** ![Guy](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/guy/32/88_2.png) [@Guy](https://forums.sketchup.com/u/Guy)\ **Post date:** [November 18, 2020, 12:39pm UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/5 "2020-11-18T12:39:06Z")
They changed the file format so that SketchUp 2021 can open newer formats when they are released. ---
**Author:** ![Box](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/box/32/235164_2.png) [@Box](https://forums.sketchup.com/u/Box)\ **Post date:** [November 18, 2020, 12:50pm UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/6 "2020-11-18T12:50:00Z")
Fair enough, I just struggle to understand how you can have something that can cope with future changes when you don’t know what those changes might be. It’s not something I know anything about so I’ll just smile and wave and disappear back into the wall. ---
**Author:** ![ene\_su](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/ene_su/32/103091_2.png) [@ene\_su](https://forums.sketchup.com/u/ene_su)\ **Post date:** [November 18, 2020, 12:55pm UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/7 "2020-11-18T12:55:53Z")
As Guy says, it’s SU 2021 that is able to open files from the future versions, not earlier versions opening 2021 files. From a development point of view this is a new feature in SU 2021, as the whole file format has been reworked to allow for forward compatibility, but for end users this won’t be visible until the next SU version. ---
**Author:** ![dezmo](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/dezmo/32/51058_2.png) [@dezmo](https://forums.sketchup.com/u/dezmo)\ **Post date:** [November 18, 2020, 1:12pm UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/8 "2020-11-18T13:12:13Z")
I guess the developers are planning future versions “incremental” so that older programs take what they understand and ignore the rest. But even the part that is taken out still makes a drawing, only the part that he doesn’t understand anyway will not there. Very-very Rough example: > **2020.skp** > “edge1, edge2, edge3 > edge1, edge2, edge3 forsm face > edge1, edge2, edge3 forsm group > group is visible on scene1 > group have a Tag1” > **2021.skp** > “edge1, edge2, edge3 > edge1, edge2, edge3 forsm face > edge1, edge2, edge3 forsm group > group have a Tag1 > Tag1 is a Triangles folder” > **2022.skp** > “edge1, edge2, edge3 > edge1, edge2, edge3 forsm face > edge1, edge2, edge3 forsm group > group is visible on scene1 > group have a Tag1 > Tag1 is a Triangles folder > scene1 is in Not animated folder” ---
**Author:** ![slbaumgartner](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/slbaumgartner/32/7302_2.png) [@slbaumgartner](https://forums.sketchup.com/u/slbaumgartner)\ **Post date:** [November 18, 2020, 1:17pm UTC](https://forums.sketchup.com/t/2021-file-format-compatibility-with-older-versions/142780/9 "2020-11-18T13:17:22Z")
I know nothing about the details of the new 2021 file format, but there have been numerous other extensible formats in the past. Usually they work via content blocks with identifying codes and readers just ignore blocks with codes they don’t recognize. There are formats that enable proprietary extensions that way. Those blocks can’t be processed by any other vendor’s reader.