# Information on software versions **URL:** \ **Category:** Wiki\ **Created:** [August 2, 2021, 9:23am UTC](https://community.mrtrix.org/t/information-on-software-versions/5091 "2021-08-02T09:23:32Z")\ **Posts on this page:** 1\ **Page:** 1
**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 2, 2021, 9:23am UTC](https://community.mrtrix.org/t/information-on-software-versions/5091/1 "2021-08-02T09:23:32Z")
The purpose of this Wiki page is to explain how the software version information works in _MRtrix3_, and include details that may be used in response to frequent user questions. ## Semantic Versioning As of the official production release of _MRtrix3_ in April 2020 ([version `3.0.0`](https://community.mrtrix.org/t/mrtrix-3-0-0-has-arrived/3558)), _MRtrix3_ now follows [Semantic Versioning](https://semver.org/). This means that the naming convention of new updates will remain consistent. The basic structure is as follows: - _Major_: These are updates where the _first_ of the three numbers is incremented; i.e. `x.0.0`. Given that the changes from MRtrix version 0.2 to version 3.0.0 took over a decade, this is unlikely to occur in the near future. - _Minor_: These are updates where the _second_ of the three numbers is incremented; i.e. `3.x.0`. Such updates involve the addition of new features and/or the modification of existing features (where the outcomes of the use of those features changes). In the _MRtrix3_ [repository](https://github.com/MRtrix3/mrtrix3), modifications that are contributed to such a pending update are made on the Git branch called “`dev`”. - _Patch_: These are updates where the _third_ of the three numbers is incremented; i.e. `3.0.x`. Such updates only involve the rectification of outright bugs or comparable issues, where the previous behaviour was unambiguously incorrect. In the _MRtrix3_ [repository](https://github.com/MRtrix3/mrtrix3), modifications that are contributed to such a pending update are made on the Git branch called “`master`”; as such, anyone who builds _MRtrix3_ from the source code, and does not deviate away from the default `master` branch, will in fact _not_ be compiling the most recent update, but additionally any fixes that have been applied to that version but have not yet been tagged as another update. As such, for scientific experiments that rely on consistency of software behaviour, one will generally want to _not_ apply _minor_ updates. For _patch_ updates, users are encouraged to read in detail the changelogs that are prepared alongside each update. If there are no erroneous behaviours that may have affected one’s own experimentation, then such updates are safe to apply, and may result in greater stability in other areas. If however there has been erroneous behaviour identified and rectified in an update that may be relevant to your data, then re-processing of those data with the updated version is generally recommended. ## Older software versions Prior to the transition to Semantic Versioning, the software versions were as follows: - [`3.0_RC3` (May 2018)](https://community.mrtrix.org/t/mrtrix-3-0-release-candidate-3/1624) - [`3.0_RC2` (July 2017)](https://community.mrtrix.org/t/mrtrix-3-0-release-candidate-2/1065) - [`3.0_RC1` (April 2017)](https://community.mrtrix.org/t/mrtrix3-version-3-0-release-candidate-1/851) - `0.3.x` (earlier) Note that while a tagged version “`3.0_RC4`” exists, this tag was generated for the purpose of testing release / deployment mechanisms, and is [not intended for wider use](https://community.mrtrix.org/t/avoid-version-3-0-rc4-not-for-deployment/3175). ## Querying software version The specific version of _MRtrix3_ that you have installed is reported at the very top-left of the inline help page: ```plaintext $ mrconvert -help MRtrix 3.0.3 mrconvert Aug 2 2021 mrconvert: part of the MRtrix3 package SYNOPSIS Perform conversion between different file types and optionally extract a subset of the input image USAGE mrconvert [options] input output input the input image. output the output image. ``` Or alternatively you can request that information explicitly: ```plaintext $ mrconvert -version == mrconvert 3.0.3 == 64 bit release version, built Aug 2 2021, using Eigen 3.3.9 Author(s): J-Donald Tournier (jdtournier@gmail.com) and Robert E. Smith (robert.smith@florey.edu.au) Copyright (c) 2008-2021 the MRtrix3 contributors. ``` ## Online documentation The _MRtrix3_ [online documentation](https://mrtrix.readthedocs.io/en/latest/) actually contains compiled documentation corresponding to _multiple versions_ of _MRtrix3_. This can cause confusion if one looks at a version of the online documentation that differs from the version of the software actually being used. - By default, the online documentation will link to whatever corresponds to the _most recent_ version of the documentation. This is also evident from the presence of string “`latest`” in the hyperlink: `https://mrtrix.readthedocs.io/en/latest/`. This can however cause confusion if you are using a version of _MRtrix3_ that is older than such. - There may be some hyperlinks present on the Internet that link to the documentation corresponding to a specific version of the software, but that version may be older than what an individual is themselves using. The specific software version to which the documentation corresponds can be both _viewed_ and _changed_, as indicated in this screenshot: ![Docs_version](https://community.mrtrix.org/uploads/default/original/2X/8/871d478fe896d95127d1b8e160806fa3d927b987.png) In addition, you should see the following warning if you are viewing a version of the documentation that does _not_ correspond to the most recent version (which is appropriate if you are intentionally viewing the version of the documentation that corresponds to your installed _MRtrix3_ version, but may cause confusion if done accidentally): ![Docs_version_warning](https://community.mrtrix.org/uploads/default/original/2X/0/0ea9b326bf8ea3a57d1d2fb2fa8778c1251dd70f.png)