# Can't open a pmx file created with older version **URL:** \ **Category:** General Questions\ **Created:** [June 25, 2025, 11:19am UTC](https://prepomax.discourse.group/t/cant-open-a-pmx-file-created-with-older-version/2797 "2025-06-25T11:19:07Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![gnikol](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/gnikol/32/3970_2.png) [@gnikol](https://prepomax.discourse.group/u/gnikol)\ **Post date:** [June 25, 2025, 11:19am UTC](https://prepomax.discourse.group/t/cant-open-a-pmx-file-created-with-older-version/2797/1 "2025-06-25T11:19:07Z")
Hi, I tried to open a model I have made some time ago, but the file was not opening with version 2.3.5. Viewing the first record of the pmx file, I see it was created with version 2.1.11, so I finally opened it using version 2.2.0 Is it possible to transfer that file to the new version 2.3.5? ![screenshot.14](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/4/46d84f722c1289bcaec2e7b340e02e8033fa88d6.jpeg) I tried to upload the pmx file but it is larger than 10 MB (almost 26) Since I have several files created with older versions, so it is important for me to know if I can transfer them to the new version of the program Thanks in advance George Nikolaidis ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [June 25, 2025, 1:03pm UTC](https://prepomax.discourse.group/t/cant-open-a-pmx-file-created-with-older-version/2797/2 "2025-06-25T13:03:02Z")
No, PrePoMax does not guarantee backward compatibility. That is why older versions of PrePoMAx are available online. Usually, it is possible to open old files in newer versions, but sometimes the compatibility is broken. ---
**Author:** ![gnikol](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/gnikol/32/3970_2.png) [@gnikol](https://prepomax.discourse.group/u/gnikol)\ **Post date:** [June 26, 2025, 7:29am UTC](https://prepomax.discourse.group/t/cant-open-a-pmx-file-created-with-older-version/2797/3 "2025-06-26T07:29:48Z")
I built from scatch a new model in version 2.3.5. After saving it and closing the program, I was unable to reopen the file using the same version (2.3.5) ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [June 26, 2025, 4:37pm UTC](https://prepomax.discourse.group/t/cant-open-a-pmx-file-created-with-older-version/2797/4 "2025-06-26T16:37:16Z")
I tried it now and it works for me. Can you easily sync the source files and try again? In the meantime, the working version is 2.3.6. ---
**Author:** ![gnikol](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/gnikol/32/3970_2.png) [@gnikol](https://prepomax.discourse.group/u/gnikol)\ **Post date:** [June 27, 2025, 8:15am UTC](https://prepomax.discourse.group/t/cant-open-a-pmx-file-created-with-older-version/2797/5 "2025-06-27T08:15:52Z")
Thank you for your response. I’ll try 2.3.6 when it becomes available in the download page. What does “sync the source files” mean? I verified that my model was built on 2.3.5. I downloaded 2.3.5 again, but it’s still unable to read the model. The error message in the command line is the following: 06/27/25 11:01:34 Running command: C:\Users\user\Desktop\PrePoMax v2.3.5 dev\NetGen\NetGenMesher.exe BREP\_VISUALIZATION “C:\Users\user\Desktop\PrePoM… 06/27/25 11:01:34 ax v2.3.5 dev\Temp\geometry.brep” “C:\Users\user\Desktop\PrePoMax v2.3.5 dev\Temp\geometry.vis” 0.01 06/27/25 11:01:34 Ng\_OCC\_Load\_BREP 06/27/25 11:01:34 Highest entry in topology hierarchy: 06/27/25 11:01:34 File was not written with this version of the topology 06/27/25 11:01:34 Error reading in BREP File: C:\Users\user\Desktop\PrePoMax v2.3.5 dev\Temp\geometry.brep I can build again my model on 2.3.0 whitch is stable for me, but I’m afraid it will not be compatible with the newer versions. Thanks again, George Nikolaidis