Slicer 4.8.1 release and transition to Qt5 and VTK9

Hi Slicers,

Next week, I suggest we release Slicer 4.8.1 based of the current master.

Then, we will toggle the default version of Qt, VTK as well as the C++ version to Qt5, VTK9 and C++11.

Let us know what you think.



I am so excited for these changes! I can’t wait for C++11 to be the default. I think that the added checks and extended capabilities of C++11 will make the overall code base much stronger in the long run.



Hi Slicers,

If tomorrow dashboard is green and unless there is any objection, we will release Slicer 4.8.1 based on current master (*).

(*) current master: This means cherry-picking all commits since the release onto slicer/Slicer@master-48 branch


VMTK extension packaging on Mac broke by the changes done right after releasing 4.8.0. It means that after 4.8.1 is merged, VMTK will not be available for Mac in 4.8.1. @jcfr Could you have a look and see if you can fix it? See details here:

Most likely related to r26488, I will have a look asap.

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VMTK extension packaging

This is the last outstanding issue. As soon as this is addressed, most likely tomorrow, I will cut the release.



  • The VMTK issue should now be fixed. Changes were specific to the extension. See PR vmtk/vmtk#209

  • The slicer-4.8 maintenance branch is currently being updated and Slicer 4.8.1 will be tagged shortly.

all of that from above the Atlantic at 37001 feet (or 11280m)

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Packages for Slicer 4.8.1 are currently being generated.

Once this is complete, the regular nightly builds will start.


  • At first, packages for Slicer 4.8.1 will not be available on They first have to be marked as released. Also the windows packages will have to be signed.

    • In the mean time, you will be able to download the packages directly from CDash clicking on the icon near each build.

    • The process will be completed in the coming days. Thanks for your patience

  • Expect some delay, since additional installer are being generated. Extensions build will take a little longer before being available.

  • Starting today, extensions for Slicer 4.8.0 will NOT be built anymore. Instead, extensions for Slicer 4.8.1 will be built daily.


The process will be completed in the coming days. Thanks for your patience

Slicer 4.8.1 packages have been marked as released (see and should show up on shortly.


Are these items below what is still pending before the switch can be flipped?

As we have a functional stable release, I think we can afford to have some limitations in nightly releases. I would vote for switching now.

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MacOS and Linux build will be broken. If you can wait few days, we can do
so during the project week.



Ciao @jcfr, I am just super curious about the state of the transition to Qt5/VTK9 after the project week!