# MRtrix 3.0 (release candidate 2)

**URL:** https://community.mrtrix.org/t/mrtrix-3-0-release-candidate-2/1065
**Category:** Announcements
**Tags:** update, release
**Created:** [July 31, 2017, 5:50am UTC](https://community.mrtrix.org/t/mrtrix-3-0-release-candidate-2/1065 "2017-07-31T05:50:46Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![rsmith](https://community.mrtrix.org/user_avatar/community.mrtrix.org/rsmith/32/2672_2.png) [@rsmith](https://community.mrtrix.org/u/rsmith)
#### Post date: [August 1, 2017, 10:27pm UTC](https://community.mrtrix.org/t/mrtrix-3-0-release-candidate-2/1065/3 "2017-08-01T22:27:37Z")

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### Fix to `dwipreproc` & phase encode handling

When _all_ DWI volumes are acquired with reversed phase-encoding (i.e. not just _b_=0 images for estimating the inhomogeneity field), it’s possible to take each pair of DW volumes that have the same diffusion gradient direction, and _combine_ them into a single volume, in a manner that accounts for the differences in information content when the two images are stretched / compressed relative to one another. This is performed when using the `-rpe_all` option, as well as the `-rpe_header` option if the input data are appropriate. However my initial testing of this functionality was not thorough enough, and a couple of users have encountered issues. It _should_ hopefully now be working… 😨

There’s also been corresponding changes to the management of phase encoding information in image headers. Some users may have encountered a warning regarding “invalid phase encoding tables”. While this warning will still occur with existing data, newly-generated images will erase this information when it is no longer relevant such that this warning no longer appears.

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_[View the full topic](https://community.mrtrix.org/t/mrtrix-3-0-release-candidate-2/1065)._