diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70419b09c8..04f5c8ee62 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,9 +7,25 @@ release.
 
 ## Unreleased
 
+### Breaking
+
+- BREAKING: Rename http.resend_count to http.request.resend_count.
+  ([#374](https://github.com/open-telemetry/semantic-conventions/pull/374))
 - Remove `network.protocol.name` from HTTP semconv.
   ([#398](https://github.com/open-telemetry/semantic-conventions/pull/398))
 
+### Features
+
+### Fixes
+
+- Clarify that `error.type` should be the fully-qualified exception class name
+  when it represents an exception type.
+  ([#387](https://github.com/open-telemetry/semantic-conventions/pull/387))
+- Add cardinality warning about two opt-in HTTP metric attributes
+  ([#401](https://github.com/open-telemetry/semantic-conventions/pull/401))
+- Change `server.port` from recommended to conditionally required on HTTP server semconv.
+  ([#399](https://github.com/open-telemetry/semantic-conventions/pull/399))
+
 ## v1.22.0 (2023-10-12)
 
 - Remove experimental Kafka metrics ([#338](https://github.com/open-telemetry/semantic-conventions/pull/338))
diff --git a/docs/attributes-registry/http.md b/docs/attributes-registry/http.md
index 7a62cc8498..7f8602c372 100644
--- a/docs/attributes-registry/http.md
+++ b/docs/attributes-registry/http.md
@@ -12,7 +12,7 @@
 | `http.request.header.<key>` | string[] | HTTP request headers, `<key>` being the normalized HTTP Header name (lowercase, with `-` characters replaced by `_`), the value being the header values. [1] | `http.request.header.content_type=["application/json"]`; `http.request.header.x_forwarded_for=["1.2.3.4", "1.2.3.5"]` |
 | `http.request.method` | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` |
 | `http.request.method_original` | string | Original HTTP method sent by the client in the request line. | `GeT`; `ACL`; `foo` |
-| `http.resend_count` | int | The ordinal number of request resending attempt (for any reason, including redirects). [3] | `3` |
+| `http.request.resend_count` | int | The ordinal number of request resending attempt (for any reason, including redirects). [3] | `3` |
 | `http.response.body.size` | int | The size of the response payload body in bytes. This is the number of bytes transferred excluding headers and is often, but not always, present as the [Content-Length](https://www.rfc-editor.org/rfc/rfc9110.html#field.content-length) header. For requests using transport encoding, this should be the compressed size. | `3495` |
 | `http.response.header.<key>` | string[] | HTTP response headers, `<key>` being the normalized HTTP Header name (lowercase, with `-` characters replaced by `_`), the value being the header values. [4] | `http.response.header.content_type=["application/json"]`; `http.response.header.my_custom_header=["abc", "def"]` |
 | `http.response.status_code` | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` |
diff --git a/docs/http/http-metrics.md b/docs/http/http-metrics.md
index 9b963d9c70..5341a8524b 100644
--- a/docs/http/http-metrics.md
+++ b/docs/http/http-metrics.md
@@ -76,7 +76,7 @@ of `[ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10
 <!-- semconv metric.http.server.request.duration(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` | Required |
 | [`http.response.status_code`](../attributes-registry/http.md) | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | Conditionally Required: If and only if one was received/sent. |
 | [`http.route`](../attributes-registry/http.md) | string | The matched route (path template in the format used by the respective server framework). See note below [3] | `/users/:userID?`; `{controller}/{action}/{id?}` | Conditionally Required: If and only if it's available |
@@ -86,10 +86,11 @@ of `[ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `http`; `https` | Required |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
@@ -205,6 +206,9 @@ Tracing instrumentations that do so, MUST also set `http.request.method_original
 
 SHOULD NOT be set if only IP address is available and capturing name would require a reverse DNS lookup.
 
+Warning: since this attribute may be based on the `Host` header, opting in to it may allow an attacker
+to trigger cardinality limits, degrading the usefulness of the metric.
+
 **[3]:** Determined by using the first of the following that applies
 
 - Port identifier of the [primary server host](/docs/http/http-spans.md#http-server-definitions) of the matched virtual host.
@@ -212,6 +216,9 @@ SHOULD NOT be set if only IP address is available and capturing name would requi
   if it's sent in absolute-form.
 - Port identifier of the `Host` header
 
+Warning: since this attribute may be based on the `Host` header, opting in to it may allow an attacker
+to trigger cardinality limits, degrading the usefulness of the metric.
+
 `http.request.method` has the following list of well-known values. If one of them applies, then the respective value MUST be used, otherwise a custom value MAY be used.
 
 | Value  | Description |
@@ -245,7 +252,7 @@ This metric is optional.
 <!-- semconv metric.http.server.request.body.size(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` | Required |
 | [`http.response.status_code`](../attributes-registry/http.md) | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | Conditionally Required: If and only if one was received/sent. |
 | [`http.route`](../attributes-registry/http.md) | string | The matched route (path template in the format used by the respective server framework). See note below [3] | `/users/:userID?`; `{controller}/{action}/{id?}` | Conditionally Required: If and only if it's available |
@@ -255,10 +262,11 @@ This metric is optional.
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `http`; `https` | Required |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
@@ -346,7 +354,7 @@ This metric is optional.
 <!-- semconv metric.http.server.response.body.size(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` | Required |
 | [`http.response.status_code`](../attributes-registry/http.md) | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | Conditionally Required: If and only if one was received/sent. |
 | [`http.route`](../attributes-registry/http.md) | string | The matched route (path template in the format used by the respective server framework). See note below [3] | `/users/:userID?`; `{controller}/{action}/{id?}` | Conditionally Required: If and only if it's available |
@@ -356,10 +364,11 @@ This metric is optional.
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `http`; `https` | Required |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
@@ -453,7 +462,7 @@ of `[ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10
 <!-- semconv metric.http.client.request.duration(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` | Required |
 | [`http.response.status_code`](../attributes-registry/http.md) | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | Conditionally Required: If and only if one was received/sent. |
 | [`network.protocol.version`](../general/attributes.md) | string | Version of the protocol specified in `network.protocol.name`. [3] | `1.0`; `1.1`; `2`; `3` | Recommended |
@@ -462,10 +471,11 @@ of `[ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `https`; `ftp`; `telnet` | Required |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
@@ -546,7 +556,7 @@ This metric is optional.
 <!-- semconv metric.http.client.request.body.size(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` | Required |
 | [`http.response.status_code`](../attributes-registry/http.md) | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | Conditionally Required: If and only if one was received/sent. |
 | [`network.protocol.version`](../general/attributes.md) | string | Version of the protocol specified in `network.protocol.name`. [3] | `1.0`; `1.1`; `2`; `3` | Recommended |
@@ -555,10 +565,11 @@ This metric is optional.
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `https`; `ftp`; `telnet` | Required |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
@@ -639,7 +650,7 @@ This metric is optional.
 <!-- semconv metric.http.client.response.body.size(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [2] | `GET`; `POST`; `HEAD` | Required |
 | [`http.response.status_code`](../attributes-registry/http.md) | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | Conditionally Required: If and only if one was received/sent. |
 | [`network.protocol.version`](../general/attributes.md) | string | Version of the protocol specified in `network.protocol.name`. [3] | `1.0`; `1.1`; `2`; `3` | Recommended |
@@ -648,10 +659,11 @@ This metric is optional.
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `https`; `ftp`; `telnet` | Required |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
diff --git a/docs/http/http-spans.md b/docs/http/http-spans.md
index b81b661597..7150b37a61 100644
--- a/docs/http/http-spans.md
+++ b/docs/http/http-spans.md
@@ -115,7 +115,7 @@ sections below.
 <!-- semconv trace.http.common(full) -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `name_resolution_error`; `500` | Conditionally Required: If request has ended with an error. |
+| `error.type` | string | Describes a class of error the operation ended with. [1] | `timeout`; `java.net.UnknownHostException`; `server_certificate_invalid`; `500` | Conditionally Required: If request has ended with an error. |
 | [`http.request.body.size`](../attributes-registry/http.md) | int | The size of the request payload body in bytes. This is the number of bytes transferred excluding headers and is often, but not always, present as the [Content-Length](https://www.rfc-editor.org/rfc/rfc9110.html#field.content-length) header. For requests using transport encoding, this should be the compressed size. | `3495` | Recommended |
 | [`http.request.header.<key>`](../attributes-registry/http.md) | string[] | HTTP request headers, `<key>` being the normalized HTTP Header name (lowercase, with `-` characters replaced by `_`), the value being the header values. [2] | `http.request.header.content_type=["application/json"]`; `http.request.header.x_forwarded_for=["1.2.3.4", "1.2.3.5"]` | Opt-In |
 | [`http.request.method`](../attributes-registry/http.md) | string | HTTP request method. [3] | `GET`; `POST`; `HEAD` | Required |
@@ -129,10 +129,11 @@ sections below.
 | `user_agent.original` | string | Value of the [HTTP User-Agent](https://www.rfc-editor.org/rfc/rfc9110.html#field.user-agent) header sent by the client. | `CERN-LineMode/2.15 libwww/2.17b3` | Recommended |
 
 **[1]:** If the request fails with an error before response status code was sent or received,
-`error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+`error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+or a component-specific low cardinality error identifier.
 
 If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+`error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
 The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
 Instrumentations SHOULD document the list of errors they report.
@@ -240,7 +241,7 @@ For an HTTP client span, `SpanKind` MUST be `Client`.
 <!-- semconv trace.http.client -->
 | Attribute  | Type | Description  | Examples  | Requirement Level |
 |---|---|---|---|---|
-| [`http.resend_count`](../attributes-registry/http.md) | int | The ordinal number of request resending attempt (for any reason, including redirects). [1] | `3` | Recommended: if and only if request was retried. |
+| [`http.request.resend_count`](../attributes-registry/http.md) | int | The ordinal number of request resending attempt (for any reason, including redirects). [1] | `3` | Recommended: if and only if request was retried. |
 | [`network.peer.address`](../general/attributes.md) | string | Peer address of the network connection - IP address or Unix domain socket name. | `10.1.2.80`; `/tmp/my.sock` | Recommended: If different than `server.address`. |
 | [`network.peer.port`](../general/attributes.md) | int | Peer port number of the network connection. | `65123` | Recommended: If `network.peer.address` is set. |
 | [`server.address`](../general/attributes.md) | string | Host identifier of the ["URI origin"](https://www.rfc-editor.org/rfc/rfc9110.html#name-uri-origin) HTTP request is sent to. [2] | `example.com`; `10.1.2.80`; `/tmp/my.sock` | Required |
@@ -371,7 +372,7 @@ For an HTTP server span, `SpanKind` MUST be `Server`.
 | [`network.peer.address`](../general/attributes.md) | string | Peer address of the network connection - IP address or Unix domain socket name. | `10.1.2.80`; `/tmp/my.sock` | Recommended |
 | [`network.peer.port`](../general/attributes.md) | int | Peer port number of the network connection. | `65123` | Recommended |
 | [`server.address`](../general/attributes.md) | string | Name of the local HTTP server that received the request. [4] | `example.com`; `10.1.2.80`; `/tmp/my.sock` | Recommended |
-| [`server.port`](../general/attributes.md) | int | Port of the local HTTP server that received the request. [5] | `80`; `8080`; `443` | Recommended: [6] |
+| [`server.port`](../general/attributes.md) | int | Port of the local HTTP server that received the request. [5] | `80`; `8080`; `443` | Conditionally Required: [6] |
 | [`url.path`](../url/url.md) | string | The [URI path](https://www.rfc-editor.org/rfc/rfc3986#section-3.3) component [7] | `/search` | Required |
 | [`url.query`](../url/url.md) | string | The [URI query](https://www.rfc-editor.org/rfc/rfc3986#section-3.4) component [8] | `q=OpenTelemetry` | Conditionally Required: If and only if one was received/sent. |
 | [`url.scheme`](../url/url.md) | string | The [URI scheme](https://www.rfc-editor.org/rfc/rfc3986#section-3.1) component identifying the used protocol. | `http`; `https` | Required |
diff --git a/docs/messaging/rabbitmq.md b/docs/messaging/rabbitmq.md
index fcc120f338..61f37c15d5 100644
--- a/docs/messaging/rabbitmq.md
+++ b/docs/messaging/rabbitmq.md
@@ -6,7 +6,7 @@ linkTitle: RabbitMQ
 
 **Status**: [Experimental][DocumentStatus]
 
-The Semantic Conventions for [RibbitMQ](https://www.rabbitmq.com/) extend and override the [Messaging Semantic Conventions](README.md)
+The Semantic Conventions for [RabbitMQ](https://www.rabbitmq.com/) extend and override the [Messaging Semantic Conventions](README.md)
 that describe common messaging operations attributes in addition to the Semantic Conventions
 described on this page.
 
diff --git a/model/error.yaml b/model/error.yaml
index cdfc587800..01b7b05f5f 100644
--- a/model/error.yaml
+++ b/model/error.yaml
@@ -26,6 +26,6 @@ groups:
 
           If the operation has completed successfully, instrumentations SHOULD NOT set `error.type`.
 
-          If a specific domain defines its own set of error codes (such as HTTP or gRPC status codes),
+          If a specific domain defines its own set of error identifiers (such as HTTP or gRPC status codes),
           it's RECOMMENDED to use a domain-specific attribute and also set `error.type` to capture
           all errors, regardless of whether they are defined within the domain-specific set or not.
diff --git a/model/http-common.yaml b/model/http-common.yaml
index fbea78bcc6..e2d3edfcfc 100644
--- a/model/http-common.yaml
+++ b/model/http-common.yaml
@@ -11,13 +11,14 @@ groups:
       - ref: error.type
         requirement_level:
           conditionally_required: If request has ended with an error.
-        examples: ['timeout', 'name_resolution_error', '500']
+        examples: ['timeout', 'java.net.UnknownHostException', 'server_certificate_invalid', '500']
         note: |
           If the request fails with an error before response status code was sent or received,
-          `error.type` SHOULD be set to exception type or a component-specific low cardinality error code.
+          `error.type` SHOULD be set to exception type (its fully-qualified class name, if applicable)
+          or a component-specific low cardinality error identifier.
 
           If response status code was sent or received and status indicates an error according to [HTTP span status definition](/docs/http/http-spans.md),
-          `error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error code.
+          `error.type` SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.
 
           The `error.type` value SHOULD be predictable and SHOULD have low cardinality.
           Instrumentations SHOULD document the list of errors they report.
@@ -91,7 +92,7 @@ groups:
             if it's sent in absolute-form.
           - Port identifier of the `Host` header
         requirement_level:
-          recommended: If not default (`80` for `http` scheme, `443` for `https`).
+          conditionally_required: If not default (`80` for `http` scheme, `443` for `https`).
       - ref: url.scheme
         requirement_level: required
         examples: ["http", "https"]
diff --git a/model/metrics/http.yaml b/model/metrics/http.yaml
index e9015a92d9..2596a06f08 100644
--- a/model/metrics/http.yaml
+++ b/model/metrics/http.yaml
@@ -52,6 +52,9 @@ groups:
 
           SHOULD NOT be set if only IP address is available and capturing name would require a reverse DNS lookup.
 
+          Warning: since this attribute may be based on the `Host` header, opting in to it may allow an attacker
+          to trigger cardinality limits, degrading the usefulness of the metric.
+
       - ref: server.port
         requirement_level: opt_in
         brief: >
@@ -64,6 +67,9 @@ groups:
             if it's sent in absolute-form.
           - Port identifier of the `Host` header
 
+          Warning: since this attribute may be based on the `Host` header, opting in to it may allow an attacker
+          to trigger cardinality limits, degrading the usefulness of the metric.
+
   - id: metric.http.server.request.body.size
     type: metric
     metric_name: http.server.request.body.size
diff --git a/model/registry/http.yaml b/model/registry/http.yaml
index 1d6f0192fa..05483ec79b 100644
--- a/model/registry/http.yaml
+++ b/model/registry/http.yaml
@@ -81,7 +81,7 @@ groups:
         type: string
         brief: Original HTTP method sent by the client in the request line.
         examples: ["GeT", "ACL", "foo"]
-      - id: resend_count
+      - id: request.resend_count
         type: int
         brief: >
           The ordinal number of request resending attempt (for any reason, including redirects).
diff --git a/model/trace/http.yaml b/model/trace/http.yaml
index adb3534875..c0cfdaf71c 100644
--- a/model/trace/http.yaml
+++ b/model/trace/http.yaml
@@ -31,7 +31,7 @@ groups:
     span_kind: client
     brief: 'Semantic Convention for HTTP Client'
     attributes:
-      - ref: http.resend_count
+      - ref: http.request.resend_count
         requirement_level:
           recommended: if and only if request was retried.
       - ref: server.address
diff --git a/schema-next.yaml b/schema-next.yaml
index b238dd19c5..8fe76165a9 100644
--- a/schema-next.yaml
+++ b/schema-next.yaml
@@ -9,6 +9,10 @@ versions:
         - rename_attributes:
             attribute_map:
               messaging.message.payload_size_bytes: messaging.message.body.size
+        # https://github.com/open-telemetry/opentelemetry-specification/pull/374
+        - rename_attributes:
+            attribute_map:
+              http.resend_count: http.request.resend_count
     metrics:
       changes:
         # https://github.com/open-telemetry/semantic-conventions/pull/224