diff --git a/build.gradle b/build.gradle
index f5d1de7be..e5f29da18 100644
--- a/build.gradle
+++ b/build.gradle
@@ -132,7 +132,8 @@ spec_schemas.dependsOn download_core30_rng
 
 def schemaList = ["xproc.rnc", "xproc.rng",
                   "xproc10.rnc", "xproc10.rng",
-                  "xproc30.rnc", "xproc30.rng"]
+                  "xproc30.rnc", "xproc30.rng",
+                  "xproc31.rnc", "xproc31.rng"]
 
 schemaList.each { schema ->
   def taskname = "download_" + schema.replace(".", "_")
@@ -324,6 +325,7 @@ task xproc_assets(dependsOn: [ "xproc:images", "xproc_web_assets", "xproc_schema
         include "xproc.rn*"
         include "xproc10.rn*"
         include "xproc30.rn*"
+        include "xproc31.rn*"
       }
     }
   }
diff --git a/src/main/xml/bibliography.xml b/src/main/xml/bibliography.xml
index 817bca776..ba0a477b6 100644
--- a/src/main/xml/bibliography.xml
+++ b/src/main/xml/bibliography.xml
@@ -31,6 +31,12 @@ Step Library</citetitle>.
 Norman Walsh, Achim Berndzen, Gerrit Imsieke and Erik Siegel, editors.
 </bibliomixed>
 
+<bibliomixed xml:id="steps31"><abbrev>Steps 3.1</abbrev>
+<citetitle xlink:href="https://spec.xproc.org/3.1/steps/">XProc 3.1: Standard
+Step Library</citetitle>.
+Norman Walsh, Achim Berndzen, Gerrit Imsieke and Erik Siegel, editors.
+</bibliomixed>
+
 <bibliomixed xml:id="xproc30-steps"><abbrev>XProc 3.0 Steps</abbrev>
 <citetitle xlink:href="https://spec.xproc.org/">XProc 3.0 Steps:
 An Introduction</citetitle>.
diff --git a/tools/xsl/rngsyntax.xsl b/tools/xsl/rngsyntax.xsl
index 3074d601d..3852868ce 100644
--- a/tools/xsl/rngsyntax.xsl
+++ b/tools/xsl/rngsyntax.xsl
@@ -251,10 +251,10 @@
   <xsl:param name="avt" select="()"/>
 
   <!-- A totally special case: allow the version attribute to be of type xs:decimal,
-       but display its fixed value as "3.0" without the quotation marks that make
+       but display its fixed value as "3.1" without the quotation marks that make
        it look like a string. -->
 
-  <ss:attribute name="{@name}" optional="{$repeat}" avt="false" type="3.0"/>
+  <ss:attribute name="{@name}" optional="{$repeat}" avt="false" type="3.1"/>
 </xsl:template>
 
 <xsl:template match="rng:attribute[@name]" priority="10">
diff --git a/xproc/src/main/examples/choose.xml b/xproc/src/main/examples/choose.xml
index 6e83e6239..947fa7606 100644
--- a/xproc/src/main/examples/choose.xml
+++ b/xproc/src/main/examples/choose.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/doctemp-1.xml b/xproc/src/main/examples/doctemp-1.xml
index d93833640..9cd9c7a3d 100644
--- a/xproc/src/main/examples/doctemp-1.xml
+++ b/xproc/src/main/examples/doctemp-1.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 xmlns:c="http://www.w3.org/ns/xproc-step"
-                name="main" version="3.0">
+                name="main" version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 <p:option name="username" required="true"/>
diff --git a/xproc/src/main/examples/doctemp-2.xml b/xproc/src/main/examples/doctemp-2.xml
index 121c6c350..103cde44d 100644
--- a/xproc/src/main/examples/doctemp-2.xml
+++ b/xproc/src/main/examples/doctemp-2.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 xmlns:c="http://www.w3.org/ns/xproc-step"
-                name="main" version="3.0">
+                name="main" version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 <p:option name="username" required="true"/>
diff --git a/xproc/src/main/examples/doctemp-3.xml b/xproc/src/main/examples/doctemp-3.xml
index 70c08f52c..58dae9050 100644
--- a/xproc/src/main/examples/doctemp-3.xml
+++ b/xproc/src/main/examples/doctemp-3.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                name="main" version="3.0">
+                name="main" version="3.1">
 <p:output port="result">
   <p:pipe step="vars" port="result"/>
 </p:output>
diff --git a/xproc/src/main/examples/exclude-pfx.xml b/xproc/src/main/examples/exclude-pfx.xml
index c436bd4ae..156192f7c 100644
--- a/xproc/src/main/examples/exclude-pfx.xml
+++ b/xproc/src/main/examples/exclude-pfx.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 xmlns:c="http://www.w3.org/ns/xproc-step"
-                version="3.0">
+                version="3.1">
   <p:output port="result" serialization="map { 'indent': true() }"/>
 
   <p:identity xmlns:a="http://example.com/a"
diff --git a/xproc/src/main/examples/fig1-abbr.xml b/xproc/src/main/examples/fig1-abbr.xml
index 670b2ee55..bab9b9a04 100644
--- a/xproc/src/main/examples/fig1-abbr.xml
+++ b/xproc/src/main/examples/fig1-abbr.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 name="xinclude-and-validate"
-                version="3.0">
+                version="3.1">
   <p:input port="source" primary="true"/>
   <p:input port="schemas" sequence="true"/>
   <p:output port="result"/>
diff --git a/xproc/src/main/examples/fig1.xml b/xproc/src/main/examples/fig1.xml
index ce963cd6a..a2aed6283 100644
--- a/xproc/src/main/examples/fig1.xml
+++ b/xproc/src/main/examples/fig1.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 name="xinclude-and-validate"
-                version="3.0">
+                version="3.1">
   <p:input port="source" primary="true"/>
   <p:input port="schemas" sequence="true"/>
   <p:output port="result">
diff --git a/xproc/src/main/examples/fig2.xml b/xproc/src/main/examples/fig2.xml
index 62761e39f..34bafc9a9 100644
--- a/xproc/src/main/examples/fig2.xml
+++ b/xproc/src/main/examples/fig2.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 name="xinclude-and-validate"
-                version="3.0">
+                version="3.1">
   <p:input port="source"/>
   <p:input port="schemas" sequence="true"/>
   <p:output port="result"/>
diff --git a/xproc/src/main/examples/for-each.xml b/xproc/src/main/examples/for-each.xml
index b6fdf4f30..a1a8e75ed 100644
--- a/xproc/src/main/examples/for-each.xml
+++ b/xproc/src/main/examples/for-each.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/group.xml b/xproc/src/main/examples/group.xml
index 584121f8c..1590e217a 100644
--- a/xproc/src/main/examples/group.xml
+++ b/xproc/src/main/examples/group.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/identity.xml b/xproc/src/main/examples/identity.xml
index f3d94026a..c79f0203b 100644
--- a/xproc/src/main/examples/identity.xml
+++ b/xproc/src/main/examples/identity.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1">
 
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/input-doc.xml b/xproc/src/main/examples/input-doc.xml
index 170b48893..58075fb7d 100644
--- a/xproc/src/main/examples/input-doc.xml
+++ b/xproc/src/main/examples/input-doc.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1">
 <p:output port="result"/>
 <p:identity name="irrelevant">
 
diff --git a/xproc/src/main/examples/input-select.xml b/xproc/src/main/examples/input-select.xml
index 309700de5..5e61e496a 100644
--- a/xproc/src/main/examples/input-select.xml
+++ b/xproc/src/main/examples/input-select.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc"  version="3.0">
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc"  version="3.1">
 <p:output port="result"/>
 <p:identity>
 
diff --git a/xproc/src/main/examples/opns-2.xml b/xproc/src/main/examples/opns-2.xml
index f178232a4..0e61ccb13 100644
--- a/xproc/src/main/examples/opns-2.xml
+++ b/xproc/src/main/examples/opns-2.xml
@@ -1,7 +1,7 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
 	        xmlns:ex="http://example.org/ns/ex"
 	        xmlns:h="http://www.w3.org/1999/xhtml"
-                type="ex:delete-in-div" version="3.0">
+                type="ex:delete-in-div" version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 <p:option name="divchild" required="true"/>
diff --git a/xproc/src/main/examples/par1.xml b/xproc/src/main/examples/par1.xml
index 8b40674c8..6e336985d 100644
--- a/xproc/src/main/examples/par1.xml
+++ b/xproc/src/main/examples/par1.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/par1b.xml b/xproc/src/main/examples/par1b.xml
index d08741fbc..9ff9119f3 100644
--- a/xproc/src/main/examples/par1b.xml
+++ b/xproc/src/main/examples/par1b.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                name="main" version="3.0">
+                name="main" version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/parameter.xml b/xproc/src/main/examples/parameter.xml
index c38a9e71c..c38782f3d 100644
--- a/xproc/src/main/examples/parameter.xml
+++ b/xproc/src/main/examples/parameter.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-	        name="main" version="3.0">
+	        name="main" version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/pipeline-library.xml b/xproc/src/main/examples/pipeline-library.xml
index 5d393521a..ca9fcaa50 100644
--- a/xproc/src/main/examples/pipeline-library.xml
+++ b/xproc/src/main/examples/pipeline-library.xml
@@ -1,6 +1,6 @@
 <p:library xmlns:p="http://www.w3.org/ns/xproc"
 	   xmlns:px="http://example.org/ns/pipelines"
-	   version="3.0">
+	   version="3.1">
 
 <p:import href="ancillary-library.xml"/>
 <p:import href="other-pipeline.xml"/>
diff --git a/xproc/src/main/examples/pipeline.xml b/xproc/src/main/examples/pipeline.xml
index 430121804..d86d08389 100644
--- a/xproc/src/main/examples/pipeline.xml
+++ b/xproc/src/main/examples/pipeline.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/shadow.xml b/xproc/src/main/examples/shadow.xml
index 188285686..878f18800 100644
--- a/xproc/src/main/examples/shadow.xml
+++ b/xproc/src/main/examples/shadow.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc" 
-  xmlns:xs="http://www.w3.org/2001/XMLSchema" version="3.0">
+  xmlns:xs="http://www.w3.org/2001/XMLSchema" version="3.1">
   
   <p:option name="bname" as="xs:integer" select="1"/>
   <p:identity message="NAME1={$bname}">
diff --git a/xproc/src/main/examples/simple-default.xml b/xproc/src/main/examples/simple-default.xml
index 3d1961685..638cb0143 100644
--- a/xproc/src/main/examples/simple-default.xml
+++ b/xproc/src/main/examples/simple-default.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/simple-explicit.xml b/xproc/src/main/examples/simple-explicit.xml
index 5ee0115a5..12cd2aa87 100644
--- a/xproc/src/main/examples/simple-explicit.xml
+++ b/xproc/src/main/examples/simple-explicit.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1">
 <p:input port="source"/>
 <p:output port="result">
   <p:pipe step="transform" port="result"/>
diff --git a/xproc/src/main/examples/step-types-1.xml b/xproc/src/main/examples/step-types-1.xml
index f14b150cf..dd88bfb63 100644
--- a/xproc/src/main/examples/step-types-1.xml
+++ b/xproc/src/main/examples/step-types-1.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0"
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1"
   xmlns:mysteps="http://.../ns/mysteps">
 
   <p:input port="source"/>
diff --git a/xproc/src/main/examples/step-types-2.xml b/xproc/src/main/examples/step-types-2.xml
index f5a848214..9320dcff8 100644
--- a/xproc/src/main/examples/step-types-2.xml
+++ b/xproc/src/main/examples/step-types-2.xml
@@ -1,4 +1,4 @@
-<p:declare-step type="mysteps:add-timestamp-attribute" version="3.0"
+<p:declare-step type="mysteps:add-timestamp-attribute" version="3.1"
                 xmlns:p="http://www.w3.org/ns/xproc"
                 xmlns:mysteps="http://.../ns/mysteps">
   <p:input port="source"/>
diff --git a/xproc/src/main/examples/step-types-3.xml b/xproc/src/main/examples/step-types-3.xml
index 0f014da1b..b294fb7d4 100644
--- a/xproc/src/main/examples/step-types-3.xml
+++ b/xproc/src/main/examples/step-types-3.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0"
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1"
   xmlns:mysteps="http://.../ns/mysteps">
 
   <p:import href="add-timestamp-attribute.xpl"/>
diff --git a/xproc/src/main/examples/step-types-4.xml b/xproc/src/main/examples/step-types-4.xml
index b58b46e52..eb1944ef3 100644
--- a/xproc/src/main/examples/step-types-4.xml
+++ b/xproc/src/main/examples/step-types-4.xml
@@ -1,4 +1,4 @@
-<p:library version="3.0" xmlns:p="http://www.w3.org/ns/xproc" 
+<p:library version="3.1" xmlns:p="http://www.w3.org/ns/xproc" 
   xmlns:mysteps="http://.../ns/mysteps">
 
   <p:declare-step type="mysteps:add-timestamp-attribute">
diff --git a/xproc/src/main/examples/trycatch.xml b/xproc/src/main/examples/trycatch.xml
index ff93e41ae..c81ccf462 100644
--- a/xproc/src/main/examples/trycatch.xml
+++ b/xproc/src/main/examples/trycatch.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
 		xmlns:c="http://www.w3.org/ns/xproc/results"
-		version="3.0">
+		version="3.1">
 <p:output port="result"/>
 
 <p:try>
diff --git a/xproc/src/main/examples/using-names-1.xml b/xproc/src/main/examples/using-names-1.xml
index b0fb2ffaf..07bcc0f81 100644
--- a/xproc/src/main/examples/using-names-1.xml
+++ b/xproc/src/main/examples/using-names-1.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0" 
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1" 
     name="main-step">
 
   <p:input port="source" primary="true"/>
diff --git a/xproc/src/main/examples/using-names-2.xml b/xproc/src/main/examples/using-names-2.xml
index 0193311ea..44831f6c4 100644
--- a/xproc/src/main/examples/using-names-2.xml
+++ b/xproc/src/main/examples/using-names-2.xml
@@ -1,4 +1,4 @@
-<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0" 
+<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.1" 
     name="main-step">
 
   <p:input port="source" primary="true"/>
diff --git a/xproc/src/main/examples/viewport.xml b/xproc/src/main/examples/viewport.xml
index 60bf92004..f4a799b57 100644
--- a/xproc/src/main/examples/viewport.xml
+++ b/xproc/src/main/examples/viewport.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/xinclude.xml b/xproc/src/main/examples/xinclude.xml
index 903cea2c2..8b642d4cf 100644
--- a/xproc/src/main/examples/xinclude.xml
+++ b/xproc/src/main/examples/xinclude.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/xpathcontext.xml b/xproc/src/main/examples/xpathcontext.xml
index becd4fe11..8d78fb5ea 100644
--- a/xproc/src/main/examples/xpathcontext.xml
+++ b/xproc/src/main/examples/xpathcontext.xml
@@ -1,5 +1,5 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
-                xmlns:xp="x" type="xp:x" version="3.0">
+                xmlns:xp="x" type="xp:x" version="3.1">
 <p:output port="result" sequence="true"/>
 
 <p:variable name="home" select="'http://example.com/docs'"/>
diff --git a/xproc/src/main/examples/xslt-empty.xml b/xproc/src/main/examples/xslt-empty.xml
index 84a3635b6..940e5c084 100644
--- a/xproc/src/main/examples/xslt-empty.xml
+++ b/xproc/src/main/examples/xslt-empty.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/examples/xslt.xml b/xproc/src/main/examples/xslt.xml
index 6c6ec8b39..cb257a2e6 100644
--- a/xproc/src/main/examples/xslt.xml
+++ b/xproc/src/main/examples/xslt.xml
@@ -1,6 +1,6 @@
 <p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
-                version="3.0">
+                version="3.1">
 <p:input port="source"/>
 <p:output port="result"/>
 
diff --git a/xproc/src/main/xml/ancillary.xml b/xproc/src/main/xml/ancillary.xml
index 50de835db..918281300 100644
--- a/xproc/src/main/xml/ancillary.xml
+++ b/xproc/src/main/xml/ancillary.xml
@@ -9,6 +9,14 @@
 ancillary files.</para>
 
 <variablelist>
+<varlistentry>
+<term><link xlink:href="xproc31.rnc"/>, <link xlink:href="xproc31.rng"/></term>
+<listitem>
+<para>A RELAX NG Schema for XProc 3.1 pipelines, in compact or XML form.
+</para>
+</listitem>
+</varlistentry>
+
 <varlistentry>
 <term><link xlink:href="xproc30.rnc"/>, <link xlink:href="xproc30.rng"/></term>
 <listitem>
@@ -29,11 +37,11 @@ ancillary files.</para>
 <term><link xlink:href="xproc.rnc"/>, <link xlink:href="xproc.rng"/></term>
 <listitem>
 <para>A RELAX NG Schema for XProc pipelines, in compact or XML form.
-It will validate either XProc 1.0 pipelines or XProc 3.0 pipelines,
+It will validate XProc 1.0, 3.0, or 3.1 pipelines,
 depending on the value of the version attribute.
 </para>
-<para>In order to use this schema, you must also download the 1.0 and 3.0
-schemas; they are included into this one.</para>
+<para>In order to use this schema, you must also download the 1.0, 3.0, and 3.1
+schemas; they are included by reference into this one.</para>
 </listitem>
 </varlistentry>
 
diff --git a/xproc/src/main/xml/references.xml b/xproc/src/main/xml/references.xml
index 6aa0633b0..2019c986a 100644
--- a/xproc/src/main/xml/references.xml
+++ b/xproc/src/main/xml/references.xml
@@ -7,7 +7,7 @@
 <section xml:id="normative-references">
   <title>Normative References</title>
   <bibliolist>
-    <bibliomixed xml:id="steps30"/>
+    <bibliomixed xml:id="steps31"/>
     <bibliomixed xml:id="xml-infoset-rec"/>
     <bibliomixed xml:id="xml10"/>
     <bibliomixed xml:id="xmlns10"/>
diff --git a/xproc/src/main/xml/specification.xml b/xproc/src/main/xml/specification.xml
index 03164d487..e36b15115 100644
--- a/xproc/src/main/xml/specification.xml
+++ b/xproc/src/main/xml/specification.xml
@@ -111,7 +111,7 @@ far as the pipeline is concerned. Compound steps control the execution
 of other steps, which they include in the form of one or more
 subpipelines.</para>
 
-<para><biblioref linkend="steps30"/>
+<para><biblioref linkend="steps31"/>
 defines a standard library of steps. Pipeline implementations
 <rfc2119>may</rfc2119> support additional types of steps as well.
 </para>
@@ -248,7 +248,7 @@ it sends result documents, and options which influence its behavior.</para>
         indivisible.</para>
       <para>There are many <emphasis>types</emphasis> of atomic steps. The
         standard library of atomic steps is described in <biblioref
-          linkend="steps30"/>, but implementations <rfc2119>may</rfc2119>
+          linkend="steps31"/>, but implementations <rfc2119>may</rfc2119>
         provide others as well. <impl>It is
           <glossterm>implementation-defined</glossterm> what additional step
           types, if any, are provided. </impl> Each use, or instance, of an
@@ -559,7 +559,7 @@ map{'serialization':
 <section xml:id="document-types">
 <title>Document Types</title>
 
-<para>XProc 3.0 has been designed to make it possible to process any kind of
+<para>XProc 3.1 has been designed to make it possible to process any kind of
 document. Each document has a representation in the <biblioref linkend="xpath-datamodel"/>.
 This is necessary so that any kind of document can be passed as an argument to XPath functions,
 such as <function>p:document-properties</function>.
@@ -985,7 +985,7 @@ step signatures are fixed and shared by all instances. There is no
 mechanism for a pipeline author to declare that an atomic step has a
 signature that varies. However, implementors may provide such
 mechanisms and other specifications may depend upon them.
-Such steps are “magic” and XProc 3.0 makes no effort to provide
+Such steps are “magic” and XProc 3.1 makes no effort to provide
 a mechanism to define them.</para>
 </note>
 
@@ -1029,11 +1029,11 @@ content types, that they accept, see <xref linkend="specified-content-types"/>.<
           intermediate results produced by steps in the pipeline have base URIs. <impl>Whether (and
             when and how) or not the intermediate results that pass between steps are ever written
             to a filesystem is <glossterm>implementation-dependent</glossterm>.</impl></para>
-        <para><impl>In Version 3.0 of XProc, how (or if) implementers provide local resolution
+        <para><impl>In Version 3.1 of XProc, how (or if) implementers provide local resolution
             mechanisms and how (or if) they provide access to intermediate results by URI is
               <glossterm>implementation-defined</glossterm>.</impl>
         </para>
-        <para>Version 3.0 of XProc does not require implementations to guarantee that multiple
+        <para>Version 3.1 of XProc does not require implementations to guarantee that multiple
           attempts to dereference the same URI always produce the same results.</para>
         <note xml:id="note-unsatisfying">
           <para>On the one hand, this is a somewhat unsatisfying state of affairs because it leaves
@@ -1350,7 +1350,7 @@ is good practice.</para>
           take account of prefix information in creating new namespace bindings, to minimize
           negative impact on prefixed names in content.</para>
         <para><impl>Except for cases which are specifically called out in <biblioref
-              linkend="steps30"/>, the extent to which namespace fixup, and other checks for
+              linkend="steps31"/>, the extent to which namespace fixup, and other checks for
             outputs which cannot be serialized, are performed on intermediate outputs is
               <glossterm>implementation-defined</glossterm>.</impl></para>
         <para>Whenever an implementation serializes XML, for example for pipeline
@@ -1433,7 +1433,7 @@ as they are available statically.</para>
 
 <para>Consider:</para>
 
-<programlisting language="xml"><![CDATA[<p:declare-step version="3.0"
+<programlisting language="xml"><![CDATA[<p:declare-step version="3.1"
                 xmlns:p="http://www.w3.org/ns/xproc">
   <p:input port="source"/>
   <p:option name="A" static="true"
@@ -1869,8 +1869,8 @@ specified.</para>
 <methodparam><type>xs:string</type><parameter>version</parameter></methodparam>
 </methodsynopsis>
 
-<para>A version 3.0 processor will return <literal>true()</literal> when
-<code>p:version-available('3.0')</code> is evaluated.</para>
+<para>A version 3.1 processor will return <literal>true()</literal> when
+<code>p:version-available('3.1')</code> is evaluated.</para>
 
 <para>The <function>p:version-available</function> function behaves
 normally during static analysis.</para>
@@ -3351,8 +3351,8 @@ Variable names are always expressed as
 <section xml:id="versioning-considerations">
 <title>Versioning Considerations</title>
 
-<para>A pipeline author <rfc2119>may</rfc2119> identify the version of XProc
-for which a particular pipeline was authored by setting the
+<para>Pipelines identify the version of XProc they are authored against
+with the
 <tag class="attribute">version</tag> attribute. The
 <tag class="attribute">version</tag> attribute can be specified on
 <tag>p:declare-step</tag> or <tag>p:library</tag>.
@@ -3364,7 +3364,7 @@ the <tag class="attribute">version</tag> attribute <rfc2119>must</rfc2119> be a
 <type>xs:decimal</type>.</error></para>
 
 <para>The version of XProc defined
-by this specification is “<literal>3.0</literal>”.</para>
+by this specification is “<literal>3.1</literal>”.</para>
 
 <para>A pipeline author <rfc2119>must</rfc2119> identify the version of XProc
 on the document element of a pipeline document.
@@ -3373,16 +3373,47 @@ required
 <tag class="attribute">version</tag> attribute
 is not present.</error></para>
 
-<para>The version identified applies
-to the element on which the
-<tag class="attribute">version</tag> attribute appears and all of its descendants,
-unless or until another version is explicitly identified.</para>
+<para>The version identified applies to the element on which the <tag
+class="attribute">version</tag> attribute appears and all of its
+descendants, unless or until another version is explicitly
+identified.</para>
 
-<para>XProc 3.0 takes a draconian approach to versioning.
-<error code="S0060">It
-is a <glossterm>static error</glossterm> if the processor encounters
-an explicit request for a version of the language other than “3.0”.</error>
+<para>An XProc 3.1 processor <rfc2119>must</rfc2119> accept pipelines
+labeled with version “3.1”. It <rfc2119>should</rfc2119> also accept
+pipelines labeled with version “3.0”.</para>
+
+<itemizedlist>
+<listitem>
+<para>If a 3.1 processor accepts pipelines
+labeled with version “3.0”, it <rfc2119>must</rfc2119>
+process them as if they were labeled “3.1”. In this case, the
+acceptable versions are “3.0” and “3.1”.
 </para>
+</listitem>
+<listitem>
+<para>Alternatively, an XProc 3.1 processor <rfc2119>may</rfc2119> reject
+pipelines labeled with version “3.0”. In this case, the only acceptable version
+is “3.1”.</para>
+</listitem>
+</itemizedlist>
+
+<note>
+<title>A pragmatic approach to 3.0 and 3.1</title>
+<para>In practice, implementations are expected to treat version “3.0”
+as a synonym for version “3.1”. Although there are technically a few
+backwards incompatiblities between 3.1 and 3.0, all known processors
+<emphasis>have always</emphasis> implemented the behavior now defined
+in 3.1, so it is of no consequence.</para>
+<para>Requiring processors to reject pipelines labeled “3.0” would be
+hostile to users with existing pipelines. Requiring implementors to
+strictly support the 3.0 behavior on pipelines labeled “3.0”
+would, from the user’s perspective, actually introduce errors in existing pipelines.</para>
+</note>
+
+<para><error code="S0060">It is a <glossterm>static error</glossterm>
+if the processor encounters an explicit request for a version of the
+language not acceptable to the processor.</error></para>
+
       </section>
 
 
@@ -4303,7 +4334,7 @@ attribute">extension attributes</glossterm>.</error>
     <title>Steps</title>
     <para>This section describes the core language steps of XProc; the full
 vocabulary of standard, atomic steps is described in
-<biblioref linkend="steps30"/>.</para>
+<biblioref linkend="steps31"/>.</para>
 
 <section xml:id="pipelines">
 <title>Pipelines</title>
@@ -5186,7 +5217,7 @@ can provide some sort of default for the rest of the pipeline.</para>
 <para><termdef xml:id="dt-atomic-step">An <firstterm>atomic
 step</firstterm> is a step that does not contain a subpipline when it
 is invoked.</termdef> The built-in steps described in <biblioref
-linkend="steps30"/> are atomic. Steps like <tag>p:for-each</tag> and
+linkend="steps31"/> are atomic. Steps like <tag>p:for-each</tag> and
 <tag>p:try</tag> that always have a subpipline are
 <emphasis>not</emphasis> atomic.
 </para>
@@ -5248,7 +5279,7 @@ steps and the terms associated with these types:</para>
     <title>Processor-provided standard atomic steps</title>
   <para>In addition to the six step types
         described in the preceding sections, XProc provides a standard library of atomic step types.
-        The full vocabulary of standards steps is described in <biblioref linkend="steps30"/>.</para>
+        The full vocabulary of standards steps is described in <biblioref linkend="steps31"/>.</para>
     <para>In addition to these standard atomic steps, other specifications by the same standardization 
       body may define other optional steps in the XProc namespace, for example, validation or file system
     related steps.</para>
@@ -5581,7 +5612,7 @@ they are <link linkend="implicit-inlines">implicit inlines</link>.</para>
 <section xml:id="conn-prec">
 <title>Connection precedence</title>
 
-<para>XProc 3.0 introduces a number of new connection defaulting
+<para>XProc has a number of new connection defaulting
 mechanisms to make pipeline authoring easier. Defaults only apply
 if there’s no explicit connection, and they apply differently to
 primary and secondary inputs.</para>