# Help Understanding Update() in VTK9
**URL:** https://discourse.vtk.org/t/help-understanding-update-in-vtk9/7120
**Category:** Support
**Created:** [November 9, 2021, 2:34pm UTC](https://discourse.vtk.org/t/help-understanding-update-in-vtk9/7120 "2021-11-09T14:34:17Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@kayarre](https://discourse.vtk.org/u/kayarre)
#### Post date: [November 9, 2021, 2:34pm UTC](https://discourse.vtk.org/t/help-understanding-update-in-vtk9/7120/1 "2021-11-09T14:34:17Z")
I am working on updating vmtk a library that heavily depends on VTK to use vtk9.
I was able to get things building, but ran into a problem where it seems like calling `Update()` causes an abort.
I am aware of changes to how `Update()` but I can’t remember where I saw them or I am making it up.
Is there a list of “Gotchas” for porting to VTK9? specifically anything that relates to the `Update()` method?
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### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [November 15, 2021, 8:48pm UTC](https://discourse.vtk.org/t/help-understanding-update-in-vtk9/7120/2 "2021-11-15T20:48:30Z")
Which class are you calling `Update()` on? I don’t think there’s anything about the execution pipeline globally, but specific classes may have issues. What version are you upgrading from?
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### Author:  [@kayarre](https://discourse.vtk.org/u/kayarre)
#### Post date: [November 15, 2021, 10:37pm UTC](https://discourse.vtk.org/t/help-understanding-update-in-vtk9/7120/3 "2021-11-15T22:37:11Z")
Thanks @ben.boeckel
I am attempting to upgrade to VTK9 and ITK5. It appears the actual issue was in ITK. vmtk wraps some ITK classes with VTK.
It had to do with ITK changes in `ThreadedGenerateData` and was what was causing things to abort before I dug a little deeper.
I replaced it with `DynamicThreadedGenerateData` and updated the progress reporter to `TotalProgressReporter` and that seems to have fixed the issue.