# Vote to keep CMP0135

**URL:** https://discourse.cmake.org/t/vote-to-keep-cmp0135/15479
**Category:** Development
**Created:** [January 26, 2026, 5:29pm UTC](https://discourse.cmake.org/t/vote-to-keep-cmp0135/15479 "2026-01-26T17:29:48Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Fabian188](https://discourse.cmake.org/user_avatar/discourse.cmake.org/fabian188/32/2934_2.png) [@Fabian188](https://discourse.cmake.org/u/Fabian188)
#### Post date: [January 26, 2026, 5:29pm UTC](https://discourse.cmake.org/t/vote-to-keep-cmp0135/15479/1 "2026-01-26T17:29:48Z")

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I hope, I’m in the right category.

CMP0135 allows in the old setting to keep the original timestamp when loading data e.g. as external project. [https://cmake.org/cmake/help/latest/policy/CMP0135.html](https://cmake.org/cmake/help/latest/policy/CMP0135.html)

Our projects has 10 to 20 external dependencies and some like boost or vtk build quite slowly. Therefore we have a home built solution for local caching of precompiled dependencies.

We extract also our precompiled dependencies via external project. The new setting of CMP0135 destroys this approach.

So I kindly vote from my side with this use case to keep CMP0135 OLD. The deprecated warning of cmake 4 scares me :(. Sure I could find a workaround, but I thought I kindly ask to keep the current state 🙂

Thanks!

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### Author: ![Angew](https://discourse.cmake.org/user_avatar/discourse.cmake.org/angew/32/229_2.png) [@Angew](https://discourse.cmake.org/u/Angew)
#### Post date: [January 26, 2026, 5:40pm UTC](https://discourse.cmake.org/t/vote-to-keep-cmp0135/15479/2 "2026-01-26T17:40:15Z")

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Note that the same CMake version which introduced `CMP0135` also introduced the ExternalProject/FetchContent argument `DOWNLOAD_EXTRACT_TIMESTAMP <bool>`, which is also documented in the [policy’s docs](https://cmake.org/cmake/help/latest/policy/CMP0135.html), and which gives you precise control of the timestamps’ behaviour. The policy only changes the default when you don’t specify `DOWNLOAD_EXTRACT_TIMESTAMP`. Your use case seems to indicate you should specify it.

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### Author: ![Fabian188](https://discourse.cmake.org/user_avatar/discourse.cmake.org/fabian188/32/2934_2.png) [@Fabian188](https://discourse.cmake.org/u/Fabian188)
#### Post date: [January 26, 2026, 6:31pm UTC](https://discourse.cmake.org/t/vote-to-keep-cmp0135/15479/3 "2026-01-26T18:31:57Z")

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Thanks a lot! There is a German saying “Those who can read have a clear advantage”.

I fixed it, it was just some additional lines as we enforce not yet cmake 3.24.