@@ -29,13 +29,13 @@ by a registry hostname. The hostname must comply with standard DNS rules, but

 may not contain underscores. If a hostname is present, it may optionally be

 followed by a port number in the format `:8080`. If not present, the command

 uses Docker's public registry located at `registry-1.docker.io` by default. Name

-components may contain lowercase characters, digits and separators. A separator

+components may contain lowercase letters, digits and separators. A separator

 is defined as a period, one or two underscores, or one or more dashes. A name

 component may not start or end with a separator.

-A tag name may contain lowercase and uppercase characters, digits, underscores,

-periods and dashes. A tag name may not start with a period or a dash and may

-contain a maximum of 128 characters.

+A tag name must be valid ASCII and may contain lowercase and uppercase letters,

+digits, underscores, periods and dashes. A tag name may not start with a

+period or a dash and may contain a maximum of 128 characters.

 You can group your images together using names and tags, and then upload them

 to [*Share Images via Repositories*](https://docs.docker.com/engine/tutorials/dockerrepos/#/contributing-to-docker-hub).

@@ -92,7 +92,7 @@ This specification uses the following terms:

         often referred to as a tag as well, though it strictly refers to the

         full name of an image. Acceptable values for a tag suffix are

         implementation specific, but they SHOULD be limited to the set of

-        alphanumeric characters <code>[a-zA-z0-9]</code>, punctuation

+        alphanumeric characters <code>[a-zA-Z0-9]</code>, punctuation

         characters <code>[._-]</code>, and MUST NOT contain a <code>:</code>

         character.

     </dd>

@@ -105,7 +105,7 @@ This specification uses the following terms:

         <code>my-app:3.1.4</code>, <code>my-app</code> is the <i>Repository</i>

         component of the name. Acceptable values for repository name are

         implementation specific, but they SHOULD be limited to the set of

-        alphanumeric characters <code>[a-zA-z0-9]</code>, and punctuation

+        alphanumeric characters <code>[a-zA-Z0-9]</code>, and punctuation

         characters <code>[._-]</code>, however it MAY contain additional

         <code>/</code> and <code>:</code> characters for organizational

         purposes, with the last <code>:</code> character being interpreted

@@ -9,15 +9,16 @@ entire image name including the optional `TAG` after the ':'.

    present, it may optionally be followed by a port number in the format 

    `:8080`. If not present, the command uses Docker's public registry located at

    `registry-1.docker.io` by default. Name components may contain lowercase 

-   characters, digits and separators. A separator is defined as a period, one or 

+   letters, digits and separators. A separator is defined as a period, one or

    two underscores, or one or more dashes. A name component may not start or end 

    with a separator.

 **TAG**

    The tag assigned to the image to version and distinguish images with the same

-   name. The tag name may contain lowercase and uppercase characters, digits, 

-   underscores, periods and dashes. A tag name may not start with a period or a 

-   dash and may contain a maximum of 128 characters.

+   name. The tag name must be valid ASCII and may contain lowercase and

+   uppercase letters, digits, underscores, periods and hyphens. A tag name

+   may not start with a period or a hyphen and may contain a maximum of 128

+   characters.

 # EXAMPLES