diff --git a/doxygen/dox/TechnicalNotes.dox b/doxygen/dox/TechnicalNotes.dox
index 6f98f688a6e..b1c809417f0 100644
--- a/doxygen/dox/TechnicalNotes.dox
+++ b/doxygen/dox/TechnicalNotes.dox
@@ -10,6 +10,7 @@
 \li \ref MT
 \li \ref SWMR
 \li \ref VDS
+\li \ref RELVERSION
 \li \ref VFL
 
  */
@@ -26,6 +27,12 @@
 
 */
 
+/** \page RELVERSION HDF5 Library Release Version Numbers
+
+\htmlinclude LibraryReleaseVersionNumbers.html
+
+*/
+
 /** \page VFL HDF5 Virtual File Layer
 
 \htmlinclude VFL.html
@@ -67,3 +74,4 @@
 \htmlinclude intro_VDS.html
 
 */
+
diff --git a/doxygen/examples/FileImageOps.html b/doxygen/examples/FileImageOps.html
index 87dfd7b1afb..2409979ff7b 100644
--- a/doxygen/examples/FileImageOps.html
+++ b/doxygen/examples/FileImageOps.html
@@ -1,4 +1,5 @@
 <!DOCTYPE html>
+<html>
 
 <title> HDF5 File Image Operations </title>
 <!--
@@ -1606,3 +1607,4 @@ <h4 id="h5ltopen_file_image_f">6.2.1. H5LTopen_file_image_f</h4>
 </tr>
 </table>
 </body>
+</html>
diff --git a/doxygen/examples/H5.format.html b/doxygen/examples/H5.format.html
index ac1dbab683b..9b2c0651d79 100644
--- a/doxygen/examples/H5.format.html
+++ b/doxygen/examples/H5.format.html
@@ -17727,8 +17727,8 @@ <h3>VII.D. The Extensible Array Index</h3></a>
 
      <p>A description of the rationale that leads to the present
        implementation of the extensible array can be found at
-       <a href="https://svn.hdfgroup.org/hdf5doc/trunk/projects/1_10_alpha/ReviseChunks/skip_lists">
-         https://svn.hdfgroup.org/hdf5doc/trunk/projects/1_10_alpha/ReviseChunks/skip_lists</a>.
+       <a href="https://github.com/HDFGroup/hdf5doc/tree/master/projects/1_10_alpha/ReviseChunks/skip_lists">
+         https://github.com/HDFGroup/hdf5doc/tree/master/projects/1_10_alpha/ReviseChunks/skip_lists</a>.
      </p>
 
 <p>The current implementation differs from the data structure
diff --git a/doxygen/examples/LibraryReleaseVersionNumbers.html b/doxygen/examples/LibraryReleaseVersionNumbers.html
new file mode 100644
index 00000000000..57b211cd61b
--- /dev/null
+++ b/doxygen/examples/LibraryReleaseVersionNumbers.html
@@ -0,0 +1,318 @@
+<!DOCTYPE html>
+<html><head>
+<title>HDF5 Library Release Version Numbers</title>
+</head>
+
+<body>
+
+<br>
+<h2>Contents</h2>
+
+<ul>
+  <li><a href="#Introduction">Introduction</a></li>
+  <li><a href="#Definitions">Definitions</a></li>
+  <li><a href="#TrunkReleaseBranchesFeatureBranches">The Trunk, Release Branches, and Feature Branches</a></li>
+  <li><a href="#VersionSupportFromTheLibrary">Version Support from the Library</a></li>
+  <li><a href="#UseCases">Use Cases</a></li>
+<ul>
+
+<li><a href="#ApplicationVersionChecking">Application Version Checking</a></li>
+<li><a href="#ConditionalInclusions">Conditional Inclusions or Exclusions Based on the Version</a></li>
+<li><a href="#SpecifyingAFormat">Specifying a Format</a></li>
+
+</ul>
+  <li><a href="#SharedLibraryVersionNumbers">Shared Library Version Numbers</a></li>
+</ul>
+
+<h2><a name="Introduction">Introduction</a></h2>
+
+<p>HDF5 software is updated on a regular basis. These updates, known
+as releases, range in scope and size from small to large. Some updates
+may only fix bugs, and some updates may require a change in the format
+of the data file. The version numbers that are applied to updates give
+information about the kinds of changes made in the updates. This Tech
+Note describes what the version numbers mean.</p>
+
+<p>Note that this document describes release version numbers for the
+HDF5 Library. For more information, see the
+<a href="#SharedLibraryVersionNumbers">Shared Library Version Numbers</a> section at the end of this document.</p>
+
+<h2><a name="Definitions">Definitions</a></h2>
+
+<p>Each software release of the HDF5 Library is labeled with a version
+  number. The version number is a set of three integers written as HDF5-1.2.3,
+  HDF5 version 1.2 release 3, or HDF5 Release 1.2.3. The version number
+  might also include text. A patch version might be labeled HDF5-1.2.3-patch1.
+  The '5' in "HDF5" is part of the product name and will not change during
+  the life of the project.</p>
+ 
+  <p>The key components in HDF5 Library version numbers are the major version
+  number, the minor version number, the release number, and an optional text
+  string. </p>
+ 
+  <p>The first integer in a version number is the <b>major version
+  number</b>. This integer increments when there is an extensive change
+  to the file format or library API. Such a change may require files to
+  be translated and will likely require applications to be modified.  </p>
+
+  <p>The second integer, 2 in the examples above, is the <b>minor version
+  number</b>. This number is incremented when there are new features that
+  require a change in the file format. For example, a change in file format
+  was required during the change from version 1.6 to version 1.8. Stable
+  released versions of the library are given <i>even</i> minor version
+  numbers such as 1.6 and 1.8 while <i>odd</i> minor version numbers such
+  as 1.7 and 1.9 are used on the trunk for major development. See the
+  section below for more information.</p>
+
+  <p>The third integer, 3 in the examples above, is the <b>release
+  number</b>. A change in this number indicates that the library has
+  been updated. The updates might include bug fixes, performance
+  improvements, and new features that do not require a file format
+  change. </p>
+ 
+  <p>A version number might also include some text. The two current
+  possibilities are <b>patch</b> and <b>snap</b>. A patch version might
+  be made to a released version to make available a feature or a bug
+  fix. In the figure below, a patch to the 1.8.5 release is labeled
+  1.8.5-patch1. A snapshot is an intermediate posting of the software
+  in a branch or in the trunk. Snapshots are made available so that users
+  may begin to test changes in the software that affect their software.
+  The changes may range from bug fixes to new features. Snapshots are made
+  and released regularly. How regularly depends on whether the software
+  passes the tests done on each build. A possible version number for a
+  snapshot might be 1.9-snap81. This version would hold the 81st snapshot
+  off the 1.9 development branch (the current trunk). For the
+  snapshots are available at 
+  <a href="https://github.com/HDFGroup/hdf5/releases/tag/snapshot">https://github.com/HDFGroup/hdf5/releases/tag/snapshot</a>.</p>
+
+<h2><a name="TrunkReleaseBranchesFeatureBranches">The Trunk, Release Branches, and Feature Branches</a></h2>
+
+  <p>The HDF Group uses a version control system to manage the HDF5
+  project. Within the system, a trunk and branches are used to track
+  changes. The version numbers described above identify where a given
+  piece of software was produced in the system. The figure below shows
+  the general scheme.</p>
+
+<table align="center" width="500" border="0">
+    <tbody><tr valign="center" align="center">
+        <td>
+        <hr color="green" size="3">
+        <img height="400" src="trunk_branches.jpg" alt="The trunk, release branches, and feature branches"></td>
+        </tr>
+    <tr valign="center" align="left">
+        <td>
+        <hr color="green" size="1">
+        <b>Figure 1.</b> The trunk, release branches, and feature branches
+        </td>
+        </tr>
+</tbody></table>
+   
+  <p>The <b>trunk</b> is the center of the system. New features are
+  implemented in <b>feature branches</b> and aggregated in the trunk.
+  <b>Release branches</b> are then created from the trunk.</p>
+ 
+  <p>The minor version number of the trunk is always an odd number. From
+  the time of Release 1.8.0 to the first 1.10 release, the trunk will be
+  version 1.9. The trunk was version 1.7 from the time of release 1.6.0
+  until the first 1.8 release.</p>
+   
+  <p>Projects that add new features, bug fixes, and performance improvements
+  are developed on <b>feature branches</b>. When a project is completed,
+  its feature branch is merged into the trunk. In the figure above, the
+  merging of a feature branch is represented by a dashed arrow from the
+  feature branch to the trunk. If a feature requires a file format change,
+  then the feature will stay in the trunk until the next significant
+  release. This would mean in the figure above that the new feature would
+  be released in a future 1.10 release branch. If a feature does not
+  require a file format change, then it might be merged into one or more
+  release branches. This would mean in the figure above that the new
+  feature could be merged into the 1.8 branch and could be included in
+  the 1.8.6 release. If the feature was added to the 1.8.5 branch, then a
+  patch version might be released.</p>
+   
+  <p><b>Release branches</b> hold software that is distributed to general
+  users. In the figure above, a few release branches are shown below the
+  trunk. Work is done in release branches for a period of time. Branches
+  further from the trunk have less work done in them. For example, a patch
+  branch such as 1.8.5-patch1 may contain only one or two changes. A release
+  branch such as 1.8.5 may contain a number of bug fixes and new functions,
+  but these changes are small in number compared to the number of changes in
+  the 1.8 branch. </p>
+   
+  <p>We aim to make available to the public two maintenance releases a year.
+  The releases occur usually in the spring near May 15 and in the fall near
+  November 15. If two release branches are being maintained, then
+  maintenance releases may be made for each release branch. For example,
+  there was a time when both the 1.6 and 1.8 branches were actively
+  maintained. In one maintenance release, the 1.6.10 and 1.8.4 versions were
+  released at the same time. The 1.6 and 1.8 branches were both actively
+  maintained to give early adopters access to new features and to give most
+  users plenty of time to make the change to 1.8 software from 1.6.</p>
+   
+  <p>As we improve any branch, we consider the effect of any change on the
+  readability of objects. Applications built, for example, with version
+  1.8.5 will be able to read data files written with any prior version
+  of the library. So, a 1.8.5 application will be able to read a dataset
+  written with 1.4.5. A 1.8.5 application may be able to read a dataset
+  written under the 1.8.7 library if no new features, features not known
+  to 1.8.5, were used.
+
+<h2><a name="VersionSupportFromTheLibrary">Version Support from the Library</a></h2>
+
+  <p>The library provides macros and functions to query and check
+  version numbers.</p>
+
+  <p>The following constants are defined in the file <code>H5public.h</code>
+  and determine the version of the include files.</p>
+
+  <ul>
+    <li><code>H5_VERS_MAJOR</code></li>
+    <li><code>H5_VERS_MINOR</code></li>
+    <li><code>H5_VERS_RELEASE</code></li>
+    <li><code>H5_VERS_SUBRELEASE</code></li>
+    <li><code>H5_VERS_INFO</code></li>
+  </ul>
+ 
+  <p>The table below describes some of the function calls and macros
+  that can be used to query and check version numbers.</p>
+
+<table width="600" cellspacing="0" align="center">
+    <tbody><tr valign="bottom">
+        <td colspan="2" align="left" valign="bottom">
+        <b>Table 1. Version function calls and macros</b></td>
+        </tr>
+    <tr><td colspan="2"><hr color="green" size="2"></td></tr>
+    <tr valign="top">
+        <td width="35%">
+        <b>Function Call or Macro</b></td>
+        <td width="65%">
+        <b>Comments</b></td>
+    </tr><tr><td colspan="2"><hr color="green" size="1"></td></tr>
+    <tr valign="top">
+        <td><code>H5get_libversion</code></td>
+        <td>This function returns through its arguments the version
+        numbers for the library to which the application is linked.</td>
+        </tr>
+    <tr><td colspan="2"><hr color="green" size="1"></td></tr>
+    <tr valign="top">
+        <td><code>H5check</code></td>
+        <td>This macro uses the <code>H5check_version</code> function
+        to verify that the version number of the HDF5 include file used
+        to compile the application matches the version number of the
+        library to which the application is linked. This check occurs
+        automatically when the first HDF5 file is created or opened and
+        is important because a mismatch between the include files and the
+        library is likely to result in corrupted data and/or segmentation
+        faults. If a mismatch is detected, the library issues an error
+        message on the standard error stream and aborts. </td>
+        </tr>
+    <tr><td colspan="2"><hr color="green" size="1"></td></tr>
+    <tr valign="top">
+        <td><code>H5check_version</code></td>
+        <td><p>This function is called by the <code>H5check</code> macro
+        with the include file version constants. The function compares
+        its arguments to the result returned by <code>H5get_libversion</code>.
+        If a mismatch is detected, it prints an error message on the standard
+        error stream and aborts.</p>
+       
+        <p>The behavior of this function can be modified by the
+        <code>HDF5_DISABLE_VERSION_CHECK</code> environment variable. Setting
+        the environment variable to a value of =911=92 will issue a
+        warning but continue without aborting. Setting the environment
+        variable to a value of =912=92 will suppress the warning
+        and continue silently without aborting.</p></td>
+        </tr>
+    <tr><td colspan="2"><hr color="green" size="1"></td></tr>
+    <tr valign="top">
+        <td><code>H5_VERSION_GE</code> and
+        <code>H5_VERSION_LE</code></td>
+        <td>These macros compare the version of the HDF5 library being used
+        against the version number specified in the parameters. At compile
+        time, they can be used to conditionally include or exclude code
+        based on the library's version.</td>
+        </tr>
+    <tr><td colspan="2"><hr color="green" size="1"></td></tr>
+    <tr valign="top">
+        <td><code>H5Pset_libver_bounds</code></td>
+        <td>This function can be used to control the versions of the object
+        formats that will be used when creating objects in a file.  </td>
+        </tr>
+    <tr><td colspan="2"><hr color="green" size="2"></td></tr>
+</tbody></table>
+ 
+  <p>For more information on these and other function calls and macros,
+  see the <a href="https://docs.hdfgroup.org/hdf5/develop/_r_m.html"> <cite>HDF5 Reference Manual</cite></a>. </p>
+
+<h2><a name="UseCases">Use Cases</a></h2>
+
+  <p>The purpose of this section is to describe how some of the version
+  functions, macros, and constants might be used. </p>
+
+<h3><a name="ApplicationVersionChecking">Application Version Checking</a></h3>
+
+  <p>Suppose first that a developer builds an application that will read
+  from and write to an HDF5 file. When the application is compiled, a
+  version of the HDF5 Library such as 1.8.6 will be used. The version
+  constants (<code>H5_VERS_MAJOR</code>, <code>H5_VERS_MINOR</code>,
+  and <code>H5_VERS_RELEASE</code>) are included in the application when
+  it is compiled. </p>
+
+  <p>Suppose next that a user gets a copy of the application and starts it
+  up on a workstation. The executable is put into memory along with the
+  HDF5 Library. However, an application may only work successfully with
+  the version of the library with which the application was compiled. In
+  other words, the version of the library that is loaded when the applicati=
+on
+  is started must be the same version as the version of the library with
+  which the application was compiled. This is verified by the library when
+  the first HDF5 API routine is called. If an application wants to confirm
+  early in its startup procedure that the version of the library that will
+  be loaded into memory at the workstation will work with the application,
+  then it can use the <code>H5get_libversion</code> and
+  <code>H5check_version</code> function calls. </p>
+
+<h3><a name="ConditionalInclusions">Conditional Inclusions or Exclusions Based on the Version</a></h3>
+
+  <p>The <code>H5_VERSION_GE</code> and <code>H5_VERSION_LE</code> version
+  macros compare the version of the HDF5 Library being used against the
+  version number specified in the parameters. At compile time, they can be
+  used to conditionally include or exclude code based on the library's
+  version. For example, the link functions, <code>H5Lxxx</code>, are
+  new in version 1.8, and some group functions, <code>H5Gxxx</code>,
+  are deprecated in 1.8. With the <code>H5_VERSION_GE</code> macro, an
+  application could use <code>H5Ldelete</code> if the library version is
+  1.8.0 or greater, or it could use <code>H5Gunlink</code> if the library
+  version is less than 1.8.0. </p>
+
+<h3><a name="SpecifyingAFormat">Specifying a Format</a></h3>
+  <p>Suppose a data file has three datasets. It is possible that the three
+  datasets were added to the data file with applications using different
+  versions of HDF5. The different versions could be 1.4.5, 1.6.10, and
+  1.8.6. If another dataset is written to the data file, then it will be
+  written by default in the oldest format possible that has all of the
+  features needed to successfully write the dataset. If a newer feature
+  such as compact storage, a new parameter for a function, or a partially
+  compressed dataset is used, then a newer format will be used.
+  <code>H5Pset_libver_bounds</code> could be used to specify the oldest
+  format used. In the situation above, the owners of the data file might
+  want all data written to the file in the future to be in a 1.8 format
+  rather than 1.6 or 1.4. </p>
+
+<h2><a name="SharedLibraryVersionNumbers">Shared Library Version Numbers</a></h2>
+
+<p>HDF5 shared libraries utilize the
+<a href="https://www.gnu.org/software/libtool/manual/libtool.html#Versioning">
+libtool versioning system</a> in order to indicate interface
+compatibility between maintenance releases of HDF5. While we always
+attempt to maintain interface compatibility between minor maintenance
+release versions of HDF5, if we are forced to break interface
+compatibility in order to resolve a critical defect within the
+library, then the library interface version attached to the shared
+libraries for a given release will be incremented accordingly.</p>
+
+<p>Please note that this libtool version number for interface
+compatibility is unrelated to the HDF5 release version for a given
+release.</p>
+
+</body>
+</html>
diff --git a/doxygen/img/images_to_copy.dox b/doxygen/img/images_to_copy.dox
index cd4b8a50148..7bba6ef3d8d 100644
--- a/doxygen/img/images_to_copy.dox
+++ b/doxygen/img/images_to_copy.dox
@@ -7,5 +7,6 @@
 <img src=tutr-swmr1.png>
 <img src=tutrvds-snglimg.png>
 <img src=tutrvds-multimgs.png>
+<img src=trunk_branches.jpg>
 
 */
diff --git a/doxygen/img/trunk_branches.jpg b/doxygen/img/trunk_branches.jpg
new file mode 100644
index 00000000000..d373c31e032
Binary files /dev/null and b/doxygen/img/trunk_branches.jpg differ
