diff --git a/VisualCard/Parsers/VcardParser.cs b/VisualCard/Parsers/VcardParser.cs
index d88961b..6f89d7a 100644
--- a/VisualCard/Parsers/VcardParser.cs
+++ b/VisualCard/Parsers/VcardParser.cs
@@ -119,22 +119,28 @@ public Card Parse()
                         // If we have more than one argument, check for ALTID
                         if (CardVersion.Major >= 4 && type == PartType.PartsArray)
                         {
-                            if (splitArgs[0].StartsWith(VcardConstants._altIdArgumentSpecifier))
+                            var cardinality = VcardParserTools.GetPartsArrayEnumFromType(classType, CardVersion).Item2;
+                            if (cardinality != PartCardinality.MayBeOneNoAltId && cardinality != PartCardinality.ShouldBeOneNoAltId &&
+                                cardinality != PartCardinality.AtLeastOneNoAltId && cardinality != PartCardinality.AnyNoAltId)
                             {
-                                // We need ALTID to be numeric
-                                if (!int.TryParse(splitArgs[0].Substring(VcardConstants._altIdArgumentSpecifier.Length), out altId))
-                                    throw new InvalidDataException("ALTID must be numeric");
+                                // The type supports ALTID.
+                                if (splitArgs[0].StartsWith(VcardConstants._altIdArgumentSpecifier))
+                                {
+                                    // We need ALTID to be numeric
+                                    if (!int.TryParse(splitArgs[0].Substring(VcardConstants._altIdArgumentSpecifier.Length), out altId))
+                                        throw new InvalidDataException("ALTID must be numeric");
 
-                                // We need ALTID to be positive
-                                if (altId < 0)
-                                    throw new InvalidDataException("ALTID must be positive");
+                                    // We need ALTID to be positive
+                                    if (altId < 0)
+                                        throw new InvalidDataException("ALTID must be positive");
 
-                                // Here, we require arguments for ALTID
-                                if (splitArgs.Length <= 1)
-                                    throw new InvalidDataException("ALTID must have one or more arguments to specify why this instance is an alternative");
+                                    // Here, we require arguments for ALTID
+                                    if (splitArgs.Length <= 1)
+                                        throw new InvalidDataException("ALTID must have one or more arguments to specify why this instance is an alternative");
+                                }
+                                else if (splitArgs.Any((arg) => arg.StartsWith(VcardConstants._altIdArgumentSpecifier)))
+                                    throw new InvalidDataException("ALTID must be exactly in the first position of the argument, because arguments that follow it are required to be specified");
                             }
-                            else if (splitArgs.Any((arg) => arg.StartsWith(VcardConstants._altIdArgumentSpecifier)))
-                                throw new InvalidDataException("ALTID must be exactly in the first position of the argument, because arguments that follow it are required to be specified");
                         }
 
                         // Finalize the arguments
diff --git a/VisualCard/Parsers/VcardParserTools.cs b/VisualCard/Parsers/VcardParserTools.cs
index 6a9bea9..377c9f1 100644
--- a/VisualCard/Parsers/VcardParserTools.cs
+++ b/VisualCard/Parsers/VcardParserTools.cs
@@ -231,7 +231,7 @@ internal static (PartsArrayEnum, PartCardinality) GetPartsArrayEnumFromType(Type
             else if (partsArrayType == typeof(XNameInfo))
                 return (PartsArrayEnum.NonstandardNames, PartCardinality.Any);
             else if (partsArrayType == typeof(RevisionInfo))
-                return (PartsArrayEnum.Revision, PartCardinality.MayBeOne);
+                return (PartsArrayEnum.Revision, PartCardinality.MayBeOneNoAltId);
             else if (partsArrayType == typeof(BirthDateInfo))
                 return (PartsArrayEnum.Birthdate, PartCardinality.MayBeOne);
             else if (partsArrayType == typeof(AnniversaryInfo))
diff --git a/VisualCard/Parts/Enums/PartCardinality.cs b/VisualCard/Parts/Enums/PartCardinality.cs
index acd2121..c6c0a8c 100644
--- a/VisualCard/Parts/Enums/PartCardinality.cs
+++ b/VisualCard/Parts/Enums/PartCardinality.cs
@@ -41,6 +41,14 @@ internal enum PartCardinality
         /// </summary>
         ShouldBeOne,
         /// <summary>
+        /// Cardinality: * (One or more instances per vCard MAY be present.) - AltID not supported
+        /// </summary>
+        AnyNoAltId,
+        /// <summary>
+        /// Cardinality: 1* (One or more instances per vCard MUST be present.) - AltID not supported
+        /// </summary>
+        AtLeastOneNoAltId,
+        /// <summary>
         /// Cardinality: *1 (Exactly one instance per vCard MAY be present.) - AltID not supported
         /// </summary>
         MayBeOneNoAltId,