diff --git a/.github/workflows/pages.yml b/.github/workflows/pages.yml
index 9539534c..0ccb969b 100644
--- a/.github/workflows/pages.yml
+++ b/.github/workflows/pages.yml
@@ -52,7 +52,7 @@ jobs:
       - name: Build
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: CARDS=true ./docs/build.sh
+        run: CI=true CARDS=true ./docs/build.sh
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v1
         with:
diff --git a/.gitignore b/.gitignore
index d779992c..1d2d9fcb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,4 @@ dhat-heap.json
 .vscode/
 **/*.deb
 **/*.rpm
+/__pycache__/
diff --git a/docs/build.sh b/docs/build.sh
index 3ba5f89b..5ca8bad2 100755
--- a/docs/build.sh
+++ b/docs/build.sh
@@ -37,7 +37,7 @@ mdbook-linkcheck --standalone docs
 
 # Adjust path to pick up pip-installed binaries
 PATH="$HOME/.local/bin;$PATH"
-pip install --quiet mkdocs-material mkdocs-git-revision-date-localized-plugin black mkdocs-exclude
+pip install --quiet mkdocs-material mkdocs-git-revision-date-localized-plugin black mkdocs-exclude mkdocs-macros-plugin
 if test -n "${CARDS}" ; then
   pip install --quiet pillow cairosvg
 fi
diff --git a/docs/generate-toc.py b/docs/generate-toc.py
index 958e485d..fd3083c6 100755
--- a/docs/generate-toc.py
+++ b/docs/generate-toc.py
@@ -281,6 +281,10 @@ TOC = [
                 "object: addressheader",
                 "reference/addressheader",
             ),
+            Page(
+                "object: connectionmeta",
+                "reference/connectionmeta.md",
+            ),
             Page(
                 "object: keysource",
                 "reference/keysource.md",
diff --git a/docs/reference/connectionmeta.md b/docs/reference/connectionmeta.md
new file mode 100644
index 00000000..6016ed8d
--- /dev/null
+++ b/docs/reference/connectionmeta.md
@@ -0,0 +1,43 @@
+# Connection Metadata Object
+
+{{since('dev')}}
+
+This object represents a collection of metadata keys and values that
+are associated with an established incoming SMTP connection.
+
+KumoMTA populates a small number of predefined fields (see below), and allows
+your policy scripts the ability to read those values as well as write (and
+read!) additional values as needed by the local policy.  For instance, you may
+decide to compute a value after EHLO has been processed by
+[smtp_server_ehlo](events/smtp_server_ehlo.md) and access that value in a
+later SMTP event handler.
+
+Prior to calling [smtp_server_message_received](events/smtp_server_message_received.md),
+KumoMTA will copy the values from the connection metadata and use those to populate
+the [message](message/index.md) metadata.
+
+The `get_meta` and `set_meta` methods shown below are used to read and write
+metadata values.
+
+## Predefined Connection Metadata Values
+
+The following values are predefined by KumoMTA:
+
+|Name|Purpose|Since|
+|----|-------|-----|
+|`reception_protocol`|indicates the reception protocol, such as `ESMTP`|{{since('dev', inline=True)}}|
+|`received_via`|indicates the IP:port of the KumoMTA listener that is handling this session|{{since('dev', inline=True)}}|
+|`received_from`|indicates the IP:port of the sending or peer machine in this session|{{since('dev', inline=True)}}|
+
+## Available Methods
+
+### `conn_meta:get_meta(name)`
+
+Returns the value associated with *name*, or `nil` if no such value has been defined.
+Values may be predefined by KumoMTA, or may be set by policy scripts using `conn_meta:set_meta()`.
+
+
+### `conn_meta:set_meta(name, value)`
+
+Sets the value associated with *name* to *value*.  Value must be serializable as JSON; it can be simple
+strings or numbers, but may also be an array or object value.
diff --git a/docs/reference/events/get_listener_domain.md b/docs/reference/events/get_listener_domain.md
index 7c2d0fdc..6851c1d5 100644
--- a/docs/reference/events/get_listener_domain.md
+++ b/docs/reference/events/get_listener_domain.md
@@ -1,4 +1,4 @@
-# `kumo.on('get_listener_domain', function(domain, listener))`
+# `kumo.on('get_listener_domain', function(domain, listener, conn_meta))`
 
 This event is triggered by the SMTP server to retrieve information about
 either a source or destination domain to help determine whether the message
@@ -11,6 +11,12 @@ listener address.
 When the SMTP `RCPT TO` command is issued by the client, the destination
 domain is passed as the *domain* parameter to this event.
 
+{{since('dev', indent=True)}}
+    The *conn_meta* parameter represents the connection metadata and
+    can be used to share state between the various SMTP listener
+    event handlers. See [Connection Metadata](../connectionmeta.md)
+    for more information.
+
 The event is expected to return a listener-domain object constructed
 by a call to [kumo.make_listener_domain](../kumo/make_listener_domain.md),
 or a `nil` value to indicate that there is no explicit configuration.
diff --git a/docs/reference/events/smtp_server_auth_plain.md b/docs/reference/events/smtp_server_auth_plain.md
index d6eb4406..701048c5 100644
--- a/docs/reference/events/smtp_server_auth_plain.md
+++ b/docs/reference/events/smtp_server_auth_plain.md
@@ -1,4 +1,4 @@
-# `kumo.on('smtp_server_auth_plain', function(authz, authc, password))`
+# `kumo.on('smtp_server_auth_plain', function(authz, authc, password, conn_meta))`
 
 Called by the ESMTP server in response to the client issuing an `"AUTH PLAIN"`
 authentication attempt.
@@ -17,6 +17,12 @@ The event handler receives the following parameters:
   with the *password* parameter.
 * *password* - the password which belongs to the claimed *authc*
 
+{{since('dev', indent=True)}}
+    The *conn_meta* parameter represents the connection metadata and
+    can be used to share state between the various SMTP listener
+    event handlers. See [Connection Metadata](../connectionmeta.md)
+    for more information.
+
 Note that [PLAIN SASL](https://www.rfc-editor.org/rfc/rfc4616) allows for *authz*
 to be empty.  KumoMTA will assume the same value as *authc* in that case, so
 this event will always be triggered with that value.
diff --git a/docs/reference/events/smtp_server_ehlo.md b/docs/reference/events/smtp_server_ehlo.md
index 2888b5dc..db32f40a 100644
--- a/docs/reference/events/smtp_server_ehlo.md
+++ b/docs/reference/events/smtp_server_ehlo.md
@@ -1,9 +1,15 @@
-# `kumo.on('smtp_server_ehlo', function(domain))`
+# `kumo.on('smtp_server_ehlo', function(domain, conn_meta))`
 
 Called by the ESMTP server in response to the client issuing either a `"HELO"`
 or `"EHLO"` command.  The event handler is passed the *domain* parameter from
 the `HELO/EHLO` command.
 
+{{since('dev', indent=True)}}
+    The *conn_meta* parameter represents the connection metadata and
+    can be used to share state between the various SMTP listener
+    event handlers. See [Connection Metadata](../connectionmeta.md)
+    for more information.
+
 You may choose to reject the connection via [kumo.reject](../kumo/reject.md).
 
 ```lua
diff --git a/docs/reference/events/smtp_server_mail_from.md b/docs/reference/events/smtp_server_mail_from.md
index 9d4a909c..070ebe13 100644
--- a/docs/reference/events/smtp_server_mail_from.md
+++ b/docs/reference/events/smtp_server_mail_from.md
@@ -1,4 +1,4 @@
-# `kumo.on('smtp_server_mail_from', function(sender))`
+# `kumo.on('smtp_server_mail_from', function(sender, conn_meta))`
 
 Called by the ESMTP server in response to the client issuing a `"MAIL FROM"`
 command.  The event handler is passed the *sender address* parameter from
@@ -6,6 +6,12 @@ the `MAIL FROM` command.
 
 The *sender address* is an [EnvelopeAddress](../address/index.md) object.
 
+{{since('dev', indent=True)}}
+    The *conn_meta* parameter represents the connection metadata and
+    can be used to share state between the various SMTP listener
+    event handlers. See [Connection Metadata](../connectionmeta.md)
+    for more information.
+
 You may choose to reject the connection via [kumo.reject](../kumo/reject.md).
 
 ```lua
diff --git a/docs/reference/events/smtp_server_message_received.md b/docs/reference/events/smtp_server_message_received.md
index 04c6c9d2..e0474c68 100644
--- a/docs/reference/events/smtp_server_message_received.md
+++ b/docs/reference/events/smtp_server_message_received.md
@@ -1,4 +1,4 @@
-# `kumo.on('smtp_server_message_received', function(message))`
+# `kumo.on('smtp_server_message_received', function(message, conn_meta))`
 
 Called by the ESMTP server after receiving the message data.
 
@@ -10,6 +10,12 @@ The event handler will be passed a [Message](../message/index.md) object.
 The Message will always have a `Received` header prepended that captures trace
 information about the sender.
 
+{{since('dev', indent=True)}}
+    The *conn_meta* parameter represents the connection metadata and
+    can be used to share state between the various SMTP listener
+    event handlers. See [Connection Metadata](../connectionmeta.md)
+    for more information.
+
 This event is the best place to carry out a number of important policy decisions:
 
 * DKIM signing via [message:dkim_sign](../message/dkim_sign.md).
diff --git a/docs/reference/events/smtp_server_rcpt_to.md b/docs/reference/events/smtp_server_rcpt_to.md
index 47984c17..5dd77d49 100644
--- a/docs/reference/events/smtp_server_rcpt_to.md
+++ b/docs/reference/events/smtp_server_rcpt_to.md
@@ -1,4 +1,4 @@
-# `kumo.on('smtp_server_rcpt_to', function(recipient))`
+# `kumo.on('smtp_server_rcpt_to', function(recipient, conn_meta))`
 
 Called by the ESMTP server in response to the client issuing a `"RCPT TO"`
 command.  The event handler is passed the *recipient address* parameter from
@@ -6,6 +6,12 @@ the `RCPT TO` command.
 
 The *recipient address* is an [EnvelopeAddress](../address/index.md) object.
 
+{{since('dev', indent=True)}}
+    The *conn_meta* parameter represents the connection metadata and
+    can be used to share state between the various SMTP listener
+    event handlers. See [Connection Metadata](../connectionmeta.md)
+    for more information.
+
 You may choose to reject the connection via [kumo.reject](../kumo/reject.md).
 
 ```lua
diff --git a/docs/reference/kumo/configure_local_logs.md b/docs/reference/kumo/configure_local_logs.md
index 6d4e677a..b2ce9ddc 100644
--- a/docs/reference/kumo/configure_local_logs.md
+++ b/docs/reference/kumo/configure_local_logs.md
@@ -124,6 +124,7 @@ kumo.configure_local_logs {
 
 Allows configuring per-record type logging.
 
+{% raw %}
 ```lua
 kumo.configure_local_logs {
   per_record = {
@@ -156,6 +157,7 @@ kumo.configure_local_logs {
   },
 }
 ```
+{% endraw %}
 
 The keys of the `per_record` table must correspond to one of the
 record types listed below, or the special `Any` key which can be used
diff --git a/docs/userguide/configuration/logging.md b/docs/userguide/configuration/logging.md
index 6e4a010a..37a154fe 100644
--- a/docs/userguide/configuration/logging.md
+++ b/docs/userguide/configuration/logging.md
@@ -49,12 +49,14 @@ kumo.configure_local_logs {
 
 If a non-JSON format is needed for the logs, the *template* option can be used:
 
+{% raw %}
 ```lua
 kumo.configure_local_logs {
   -- ..
   template = [[{{type}} id={{ id }}, from={{ sender }} code={{ code }} age={{ timestamp - created }}]],
 }
 ```
+{% endraw %}
 
 The [Mini Jinja](https://docs.rs/minijinja/latest/minijinja/) templating engine
 is used to evalute logging templates.  The full supported syntax is [documented
@@ -64,6 +66,7 @@ here](https://docs.rs/minijinja/latest/minijinja/syntax/index.html). Any key pre
 
 Sometimes it is necessary to configure logging on a more granular basis, especially when using custom log formats. KumoMTA supports this using the *per_record* option:
 
+{% raw %}
 ```lua
 kumo.configure_local_logs {
   per_record = {
@@ -96,5 +99,6 @@ kumo.configure_local_logs {
   },
 }
 ```
+{% endraw %}
 
 This can be used to override paths, disable logs, or customize the format of specific event types.
diff --git a/mkdocs-base.yml b/mkdocs-base.yml
index 324bb977..8632e21e 100644
--- a/mkdocs-base.yml
+++ b/mkdocs-base.yml
@@ -45,8 +45,11 @@ plugins:
   - social:
       cards: !ENV [CARDS, false]
   - git-revision-date-localized:
+      enabled: !ENV [CI, false]
       enable_creation_date: true
       type: timeago
+  - macros:
+      module_name: mkdocs_macros
   - exclude:
       glob:
         - "**/_index.md"
diff --git a/mkdocs_macros.py b/mkdocs_macros.py
new file mode 100644
index 00000000..62f9d8e6
--- /dev/null
+++ b/mkdocs_macros.py
@@ -0,0 +1,46 @@
+import json
+
+# https://mkdocs-macros-plugin.readthedocs.io/en/latest/macros/
+def define_env(env):
+    @env.macro
+    # Set indent=True when you want to define a box containing version-specific info.
+    #
+    # Set inline=True when you want to define a simple inline version indicator,
+    # such as when emitting information into a table row.
+    def since(vers, indent=False, inline=False):
+
+        scope = "section"
+        expanded = ""
+        expander = "???"
+        if indent:
+            scope = "outlined box"
+            expander = "!!!"
+
+        if vers == "dev":
+            first_line = "*Since: Dev Builds Only*"
+            if scope != "section":
+                expanded = "+"
+            blurb = f"""
+    *The functionality described in this {scope} requires a dev build of KumoMTA.
+    You can obtain a dev build by following the instructions in the
+    [Installation](/userguide/installation/linux.md) section.*
+"""
+        else:
+            first_line = f"*Since: Version {vers}*"
+            blurb = f"""
+    *The functionality described in this {scope} requires version {vers} of KumoMTA,
+    or a more recent version.*
+"""
+
+        if inline:
+            return f"({first_line})"
+
+        # If we're not expandable, don't emit the expanded marker
+        if expander == "!!!":
+            expanded = ""
+
+        return f"""
+{expander}{expanded} info "{first_line}"
+{blurb}
+    <hr/>
+"""