diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java
index 657bd42a8..128f5d60e 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java
@@ -171,6 +171,7 @@ public class I18nConstants {
   public static final String FHIRPATH_NOT_IMPLEMENTED = "FHIRPATH_NOT_IMPLEMENTED";
   public static final String FHIRPATH_NO_COLLECTION = "FHIRPATH_NO_COLLECTION";
   public static final String FHIRPATH_NO_TYPE = "FHIRPATH_NO_TYPE";
+  public static final String FHIRPATH_UNKNOWN_TYPE = "FHIRPATH_UNKNOWN_TYPE";
   public static final String FHIRPATH_NUMERICAL_ONLY = "FHIRPATH_NUMERICAL_ONLY";
   public static final String FHIRPATH_OP_INCOMPATIBLE = "FHIRPATH_OP_INCOMPATIBLE";
   public static final String FHIRPATH_ORDERED_ONLY = "FHIRPATH_ORDERED_ONLY";
@@ -909,6 +910,10 @@ public class I18nConstants {
   public static final String QUESTIONNAIRE_Q_ITEM_DERIVED_ANSWER_OPTIONS_NEW = "QUESTIONNAIRE_Q_ITEM_DERIVED_ANSWER_OPTIONS_NEW";
   public static final String PRIMITIVE_MUSTHAVEVALUE_MESSAGE = "PRIMITIVE_MUSTHAVEVALUE_MESSAGE";
   public static final String PRIMITIVE_VALUE_ALTERNATIVES_MESSAGE = "PRIMITIVE_VALUE_ALTERNATIVES_MESSAGE";
+  public static final String ED_INVARIANT_NO_KEY = "ED_INVARIANT_NO_KEY";
+  public static final String ED_INVARIANT_NO_EXPRESSION = "ED_INVARIANT_NO_EXPRESSION";
+  public static final String ED_INVARIANT_EXPRESSION_CONFLICT = "ED_INVARIANT_EXPRESSION_CONFLICT";
+  public static final String ED_INVARIANT_EXPRESSION_ERROR = "ED_INVARIANT_EXPRESSION_ERROR";
 
 }
 
diff --git a/org.hl7.fhir.utilities/src/main/resources/Messages.properties b/org.hl7.fhir.utilities/src/main/resources/Messages.properties
index f55fc3577..4885f8fe5 100644
--- a/org.hl7.fhir.utilities/src/main/resources/Messages.properties
+++ b/org.hl7.fhir.utilities/src/main/resources/Messages.properties
@@ -610,7 +610,8 @@ FHIRPATH_NO_COLLECTION = Error evaluating FHIRPath expression: The function {0}
 FHIRPATH_NOT_IMPLEMENTED = Error evaluating FHIRPath expression: The function {0} is not implemented
 FHIRPATH_PARAM_WRONG = Error evaluating FHIRPath expression: The expression type {0} is not supported for parameter {1} on function {2}
 FHIRPATH_CHECK_FAILED = Error evaluating FHIRPath expression: The check {0} failed
-FHIRPATH_NO_TYPE = Error evaluating FHIRPath expression: The type ''{0}'' is unknown or not supported at {1}
+FHIRPATH_NO_TYPE = Error evaluating FHIRPath expression: No type provided at {1}
+FHIRPATH_UNKNOWN_TYPE = Error evaluating FHIRPath expression: The type ''{0}'' is unknown or not supported at {1}
 FHIRPATH_DISCRIMINATOR_NAME_ALREADY_SLICED = Error in discriminator at {0}: found a sliced element while resolving the fixed value for one of the slices
 FHIRPATH_DISCRIMINATOR_THIS_CANNOT_FIND = Problem with use of resolve() - profile {0} on {1} could not be resolved
 FHIRPATH_DISCRIMINATOR_RESOLVE_NO_TYPE = Invalid use of resolve() in discriminator - no type on element {0}
@@ -963,3 +964,8 @@ QUESTIONNAIRE_Q_ITEM_DERIVED_ANSWER_OPTIONS_NEW = The item with linkId ''{1}'' f
 PRIMITIVE_MUSTHAVEVALUE_MESSAGE = The element definition ``{0}`` in the profile ''{1}'' requires that a value be present in this element
 PRIMITIVE_VALUE_ALTERNATIVES_MESSAGE_one = The element definition ``{0}`` in the profile ''{1}'' requires that if a value is not present, the extension ''{2}'' must be present
 PRIMITIVE_VALUE_ALTERNATIVES_MESSAGE_other = The element definition ``{0}`` in the profile ''{1}'' requires that if a value is not present, one of the extensions ''{2}'' must be present
+ED_INVARIANT_NO_KEY = The invariant has no key, so the content cannot be validated
+ED_INVARIANT_NO_EXPRESSION = The invariant ''{0}'' has no computable expression, so validators will not be able to check it
+ED_INVARIANT_EXPRESSION_CONFLICT = The invariant ''{0}'' has an expression ''{1}'', which differs from the earlier expression provided of ''{2}'' (invariants are allowed to repeat, but cannot differ)
+ED_INVARIANT_EXPRESSION_ERROR = Error in invariant ''{0}'' with expression ''{1}'': {2}
+