diff --git a/draft/spec/index.html b/draft/spec/index.html
index 28aa181..dd216ca 100644
--- a/draft/spec/index.html
+++ b/draft/spec/index.html
@@ -490,6 +490,8 @@ <h2>Content Directory</h2>
               otherwise. The name of this designated sub-directory MAY be defined in the
               <a href="#inventory">inventory file</a> using the key <code>contentDirectory</code> with the value being
               the chosen sub-directory name as a string, relative to the version directory. The
+              <code>contentDirectory</code> value <span id="E0108">MUST</span> represent a direct child directory of the
+              version directory in which it is found. As such, the
               <code>contentDirectory</code> value <span id="E017">MUST NOT</span> contain the forward slash
               (<code>/</code>) path separator and <span id="E018">MUST NOT</span> be either one or two periods
               (<code>.</code> or <code>..</code>). If the key <code>contentDirectory</code> is set, it
@@ -630,8 +632,9 @@ <h2>Basic Structure</h2>
                 <dt><code>id</code></dt>
                 <dd>
                     A unique identifier for the OCFL Object. This <span id="E037">MUST</span> be unique in the local
-                    context, and <span id="W005">SHOULD</span> be a URI [[!RFC3986]]. There is no expectation that a
-                    URI used is resolvable. For example, URNs [[RFC8141]] MAY be used.
+                    context, <span id="E110">MUST NOT</span> change between versions of the same object, and <span 
+                    id="W005">SHOULD</span> be a URI [[!RFC3986]]. There is no expectation that a URI used is 
+                    resolvable. For example, URNs [[RFC8141]] MAY be used.
                 </dd>
                 <dt><code>type</code></dt>
                 <dd>
diff --git a/draft/spec/validation-codes.md b/draft/spec/validation-codes.md
index 7d33eba..eaac28c 100644
--- a/draft/spec/validation-codes.md
+++ b/draft/spec/validation-codes.md
@@ -117,7 +117,9 @@
 | E105 | 'The version number MUST be taken from the sequence of positive, base-ten integers: 1, 2, 3, etc.' | https://ocfl.io/draft/spec/#E105
 | E106 | 'The value of the manifest key MUST be a JSON object.' | https://ocfl.io/draft/spec/#E106
 | E107 | 'The value of the manifest key must be a JSON object, and each key MUST correspond to a digest value key found in one or more state blocks of the current and/or previous version blocks of the OCFL Object.' | https://ocfl.io/draft/spec/#E107
+| E108 | 'The contentDirectory value MUST represent a direct child directory of the version directory in which it is found.' | https://ocfl.io/draft/spec/#E108
 | E109 | 'When no files have been added or updated in a given version, resulting in an empty and therefore absent "content" directory, the version directory MUST include an inventory file.' | https://ocfl.io/draft/spec/#E109
+| E110 | 'A unique identifier for the OCFL Object MUST NOT change between versions of the same object.' | https://ocfl.io/draft/spec/#E110
 
 ## Warnings (corresponding with SHOULD in specification)