diff --git a/src/oaklib/implementations/simpleobo/simple_obo_implementation.py b/src/oaklib/implementations/simpleobo/simple_obo_implementation.py
index 3e0d05d1f..bcee7b2be 100644
--- a/src/oaklib/implementations/simpleobo/simple_obo_implementation.py
+++ b/src/oaklib/implementations/simpleobo/simple_obo_implementation.py
@@ -907,14 +907,14 @@ def _tv_dict(stanza: Stanza) -> Dict[str, List[str]]:
             elif tag == TAG_SUBSET:
                 if node_is_deleted:
                     continue
-                subsets1 = stanza1.simple_values(TAG_SUBSET)
-                subsets2 = stanza2.simple_values(TAG_SUBSET)
-                for subset in subsets1:
-                    if subset not in subsets2:
-                        yield kgcl.RemoveNodeFromSubset(id=_id(), about_node=t1id, in_subset=subset)
-                for subset in subsets2:
-                    if subset not in subsets1:
-                        yield kgcl.AddNodeToSubset(id=_id(), about_node=t2id, in_subset=subset)
+                xrefs1 = stanza1.simple_values(TAG_SUBSET)
+                xrefs2 = stanza2.simple_values(TAG_SUBSET)
+                for xref in xrefs1:
+                    if xref not in xrefs2:
+                        yield kgcl.RemoveNodeFromSubset(id=_id(), about_node=t1id, in_subset=xref)
+                for xref in xrefs2:
+                    if xref not in xrefs1:
+                        yield kgcl.AddNodeToSubset(id=_id(), about_node=t2id, in_subset=xref)
             elif tag == TAG_IS_A:
                 isas1 = stanza1.simple_values(TAG_IS_A)
                 isas2 = stanza2.simple_values(TAG_IS_A)
@@ -950,6 +950,21 @@ def _tv_dict(stanza: Stanza) -> Dict[str, List[str]]:
                         yield kgcl.NewSynonym(
                             id=_id(), about_node=t2id, new_value=syn[0], predicate=pred
                         )
+            elif tag == TAG_XREF:
+                if node_is_deleted:
+                    continue
+                xrefs1 = stanza1.simple_values(TAG_XREF)
+                xrefs2 = stanza2.simple_values(TAG_XREF)
+                for xref in xrefs1:
+                    if xref not in xrefs2:
+                        yield kgcl.RemoveMapping(
+                            id=_id(), about_node=t1id, object=xref, predicate=HAS_DBXREF
+                        )
+                for xref in xrefs2:
+                    if xref not in xrefs1:
+                        yield kgcl.MappingCreation(
+                            id=_id(), subject=t2id, object=xref, predicate=HAS_DBXREF
+                        )
 
     def different_from(self, entity: CURIE, other_ontology: DifferInterface) -> bool:
         t1 = self._stanza(entity, strict=False)
diff --git a/src/oaklib/interfaces/differ_interface.py b/src/oaklib/interfaces/differ_interface.py
index 36e939922..31665f02b 100644
--- a/src/oaklib/interfaces/differ_interface.py
+++ b/src/oaklib/interfaces/differ_interface.py
@@ -11,9 +11,10 @@
     Change,
     ClassCreation,
     Edge,
-    EdgeChange,
-    EdgeCreation,
     EdgeDeletion,
+    MappingCreation,
+    # MappingReplacement,
+    MappingPredicateChange,
     NewSynonym,
     NewTextDefinition,
     NodeCreation,
@@ -26,6 +27,7 @@
     NodeTextDefinitionChange,
     NodeUnobsoletion,
     PredicateChange,
+    RemoveMapping,
     RemoveNodeFromSubset,
     RemoveSynonym,
     RemoveTextDefinition,
@@ -275,34 +277,35 @@ def diff(
             if mappings_added_set:
                 for mapping in mappings_added_set:
                     predicate, xref = mapping
-                    edge_created = EdgeCreation(
+                    mapping_created = MappingCreation(
                         id=_gen_id(),
                         subject=entity,
                         predicate=predicate,
                         object=xref,
                     )
-                    yield edge_created
+                    yield mapping_created
             if mappings_removed_set:
                 for mapping in mappings_removed_set:
                     predicate, xref = mapping
-                    deleted_edge = EdgeDeletion(
+                    deleted_mapping = RemoveMapping(
                         id=_gen_id(),
-                        subject=entity,
+                        about_node=entity,
                         predicate=predicate,
                         object=xref,
                     )
-                    yield deleted_edge
+                    yield deleted_mapping
             if mapping_changed_set:
                 for changes in mapping_changed_set:
                     object, new_predicate, old_predicate = changes
-                    edge_change = EdgeChange(
+                    mapping_change = MappingPredicateChange(
                         id=_gen_id(),
-                        about_edge=Edge(subject=entity, predicate=old_predicate, object=object),
+                        about_node=entity,
+                        object=object,
                         old_value=old_predicate,
                         new_value=new_predicate,
                     )
 
-                    yield edge_change
+                    yield mapping_change
 
             # ! Subset changes
             self_subsets = set(self.terms_subsets([entity]))
diff --git a/src/oaklib/utilities/writers/change_handler.py b/src/oaklib/utilities/writers/change_handler.py
index e959c2867..3d49ecc38 100644
--- a/src/oaklib/utilities/writers/change_handler.py
+++ b/src/oaklib/utilities/writers/change_handler.py
@@ -25,15 +25,17 @@ def write_markdown_table(self, title: str, header: str, rows: List[str]) -> None
     def handle_generic_change(
         self, value: List[object], title: str, header: str, row_format: str
     ) -> None:
-        rows = [row_format.format(change=change) for change in value]
+        rows = list({row_format.format(change=change) for change in value})
         self.write_markdown_table(f"{title}: {len(rows)}", header, rows)
 
     def handle_new_synonym(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(obj.about_node)} | {obj.new_value} | {obj.predicate} |"
-            for obj in value
-        ]
+        rows = list(
+            {
+                f"| {self._format_entity_labels(obj.about_node)} | {obj.new_value} | {obj.predicate} |"
+                for obj in value
+            }
+        )
 
         # Define the header for the table
         header = "| Term | New Synonym | Predicate |"
@@ -43,11 +45,13 @@ def handle_new_synonym(self, value):
 
     def handle_edge_deletion(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.subject)} | {self._format_entity_labels(change.predicate)} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.subject)} | {self._format_entity_labels(change.predicate)} |\
                 {self._format_entity_labels(change.object)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Subject| Predicate| Object|"
@@ -57,11 +61,13 @@ def handle_edge_deletion(self, value):
 
     def handle_edge_creation(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.subject)} | {self._format_entity_labels(change.predicate)} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.subject)} | {self._format_entity_labels(change.predicate)} |\
                 {self._format_entity_labels(change.object)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Subject | Predicate | Object|"
@@ -71,12 +77,14 @@ def handle_edge_creation(self, value):
 
     def handle_edge_change(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_edge.subject)} | \
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_edge.subject)} | \
                 {self._format_entity_labels(change.about_edge.predicate)} | \
                 {self._format_entity_labels(change.old_value)} | {self._format_entity_labels(change.new_value)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Subject | Predicate | Old Object | New Object |"
@@ -86,12 +94,14 @@ def handle_edge_change(self, value):
 
     def handle_node_move(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_edge.subject)} | \
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_edge.subject)} | \
                 {self._format_entity_labels(change.about_edge.predicate)} |\
                 {self._format_entity_labels(change.about_edge.object)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Subject | Predicate | Object |"
@@ -101,13 +111,15 @@ def handle_node_move(self, value):
 
     def handle_predicate_change(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_edge.subject)} | \
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_edge.subject)} | \
                 {self._format_entity_labels(change.old_value)} |\
                 {self._format_entity_labels(change.new_value)} | \
                 {self._format_entity_labels(change.about_edge.object)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Subject | Old Predicate | New Predicate | Object |"
@@ -117,9 +129,12 @@ def handle_predicate_change(self, value):
 
     def handle_node_rename(self, value):
         # Create rows for the table
-        rows = [
-            f"| {change.about_node} | {change.old_value} | {change.new_value} |" for change in value
-        ]
+        rows = list(
+            {
+                f"| {change.about_node} | {change.old_value} | {change.new_value} |"
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| ID | Old Label | New Label |"
@@ -129,10 +144,12 @@ def handle_node_rename(self, value):
 
     def handle_remove_synonym(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |"
-            for change in value
-        ]
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |"
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Term | Removed Synonym |"
@@ -142,11 +159,13 @@ def handle_remove_synonym(self, value):
 
     def hand_synonym_predicate_change(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |\
                   {change.new_value} | {change.target} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Term | Old Predicate | New Predicate | Synonym |"
@@ -156,11 +175,13 @@ def hand_synonym_predicate_change(self, value):
 
     def handle_node_text_definition_change(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |\
                   {change.new_value} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Term | Old Text Definition | New Text Definition |"
@@ -170,11 +191,13 @@ def handle_node_text_definition_change(self, value):
 
     def handle_node_text_definition(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |\
                   {change.new_value} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
 
         # Define the header for the table
         header = "| Term | Old Text Definition | New Text Definition |"
@@ -184,7 +207,7 @@ def handle_node_text_definition(self, value):
 
     def handle_node_unobsoletion(self, value):
         # Create rows for the table
-        rows = [f"| {self._format_entity_labels(change.about_node)} |" for change in value]
+        rows = list({f"| {self._format_entity_labels(change.about_node)} |" for change in value})
 
         # Define the header for the table
         header = "| Term |"
@@ -194,7 +217,7 @@ def handle_node_unobsoletion(self, value):
 
     def handle_node_creation(self, value):
         # Create rows for the table
-        rows = [f"| {self._format_entity_labels(change.about_node)} |" for change in value]
+        rows = list({f"| {self._format_entity_labels(change.about_node)} |" for change in value})
 
         # Define the header for the table
         header = "| Term |"
@@ -204,7 +227,7 @@ def handle_node_creation(self, value):
 
     def handle_class_creation(self, value):
         # Create rows for the table
-        rows = [f"| {self._format_entity_labels(change.about_node)} |" for change in value]
+        rows = list({f"| {self._format_entity_labels(change.about_node)} |" for change in value})
 
         # Define the header for the table
         header = "| Term |"
@@ -214,7 +237,7 @@ def handle_class_creation(self, value):
 
     def handle_node_deletion(self, value):
         # Create rows for the table
-        rows = [f"| {self._format_entity_labels(change.about_node)} |" for change in value]
+        rows = list({f"| {self._format_entity_labels(change.about_node)} |" for change in value})
 
         # Define the header for the table
         header = "| Term |"
@@ -224,28 +247,34 @@ def handle_node_deletion(self, value):
 
     def handle_new_text_definition(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.new_value} |"
-            for change in value
-        ]
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.new_value} |"
+                for change in value
+            }
+        )
         header = "| Term | New Text Definition |"
         self.write_markdown_table(f"Text definitions added: {len(rows)}", header, rows)
 
     def handle_remove_text_definition(self, value):
         # Create rows for the table
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |"
-            for change in value
-        ]
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.old_value} |"
+                for change in value
+            }
+        )
         header = "| Term | Removed Text Definition |"
         self.write_markdown_table(f"Text definitions removed: {len(rows)}", header, rows)
 
     def handle_node_obsoletion_with_direct_replacement(self, value):
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} |\
                   {self._format_entity_labels(change.has_direct_replacement)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
         header = "| Term | Replacement |"
         self.write_markdown_table(f"Nodes obsoleted with replacement: {len(rows)}", header, rows)
 
@@ -255,22 +284,66 @@ def handle_node_obsoletion(self, value):
         self.write_markdown_table(f"Nodes obsoleted without replacement: {len(rows)}", header, rows)
 
     def handle_node_direct_merge(self, value):
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} |\
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} |\
                   {self._format_entity_labels(change.has_direct_replacement)} |"
-            for change in value
-        ]
+                for change in value
+            }
+        )
         header = "| Term | Replacement |"
         self.write_markdown_table(f"Nodes merged: {len(rows)}", header, rows)
 
     def handle_add_node_to_subset(self, value):
-        rows = [
-            f"| {self._format_entity_labels(change.about_node)} | {change.in_subset} |"
-            for change in value
-        ]
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | {change.in_subset} |"
+                for change in value
+            }
+        )
         header = "| Term | Subset |"
         self.write_markdown_table(f"Nodes added to subset: {len(rows)}", header, rows)
 
+    def handle_mapping_creation(self, value):
+        rows = list(
+            {
+                f"""| {self._format_entity_labels(change.subject)}
+                | {change.predicate} | {self._format_entity_labels(change.object)} |"""
+                for change in value
+            }
+        )
+        header = "| Subject | Predicate | Object |"
+        self.write_markdown_table(f"Mappings added: {len(rows)}", header, rows)
+
+    def handle_mapping_predicate_change(self, value):
+        # Create rows for the table
+        rows = list(
+            {
+                f"| {self._format_entity_labels(change.about_node)} | \
+                {self._format_entity_labels(change.old_value)} |\
+                {self._format_entity_labels(change.new_value)} | \
+                {self._format_entity_labels(change.object)} |"
+                for change in value
+            }
+        )
+
+        # Define the header for the table
+        header = "| Subject | Old Mapping Predicate | New Mapping Predicate | Object |"
+
+        # Write the "Predicate Changed" section as a collapsible markdown table
+        self.write_markdown_table(f"Mappings changed: {len(rows)}", header, rows)
+
+    def handle_remove_mapping(self, value):
+        rows = list(
+            {
+                f"""| {self._format_entity_labels(change.about_node)}
+                | {change.predicate} | {self._format_entity_labels(change.object)} |"""
+                for change in value
+            }
+        )
+        header = "| Subject | Predicate | Object |"
+        self.write_markdown_table(f"Mappings removed: {len(rows)}", header, rows)
+
     # def handle_datatype_or_language_tag_change(self, value):
     #     # Implement datatype or language tag change handling logic here
     #     logging.info("Datatype or language tag change handling not yet implemented.")
@@ -340,6 +413,9 @@ def process_changes(self, curie_or_change: Dict[str, Change]):
             "EdgeCreation": self.handle_edge_creation,
             "EdgeChange": self.handle_edge_change,
             "AddNodeToSubset": self.handle_add_node_to_subset,
+            "MappingPredicateChange": self.handle_mapping_predicate_change,
+            "MappingCreation": self.handle_mapping_creation,
+            "RemoveMapping": self.handle_remove_mapping,
             # "DatatypeOrLanguageTagChange": self.handle_datatype_or_language_tag_change,
             # "LanguageTagChange": self.handle_language_tag_change,
             # "DatatypeChange": self.handle_datatype_change,
diff --git a/tests/input/go-nucleus-modified.obo b/tests/input/go-nucleus-modified.obo
index 7df9d994d..155604b12 100644
--- a/tests/input/go-nucleus-modified.obo
+++ b/tests/input/go-nucleus-modified.obo
@@ -377,7 +377,6 @@ subset: goslim_yeast
 synonym: "cell or subcellular entity" EXACT []
 synonym: "cellular component" EXACT []
 synonym: "subcellular entity" RELATED [NIF_Subcellular:nlx_subcell_100315]
-xref: NIF_Subcellular:sao1337158144
 is_a: BFO:0000040 ! material entity
 disjoint_from: GO:0008150 ! biological_process
 
@@ -422,6 +421,7 @@ synonym: "cell nucleus" EXACT []
 synonym: "horsetail nucleus" NARROW [GOC:al, GOC:mah, GOC:vw, PMID:15030757]
 xref: NIF_Subcellular:sao1702920020
 xref: Wikipedia:Cell_nucleus
+xref: foo:test
 is_a: GO:0043231 ! intracellular membrane-bounded organelle
 disjoint_from: GO:0005737 ! cytoplasm
 relationship: in_taxon NCBITaxon:2759 ! Eukaryota
diff --git a/tests/test_cli.py b/tests/test_cli.py
index fc55d3914..399424c10 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -10,7 +10,7 @@
 import rdflib
 import yaml
 from click.testing import CliRunner
-from kgcl_schema.datamodel.kgcl import NodeChange
+from kgcl_schema.datamodel.kgcl import MappingCreation, NodeChange, RemoveMapping
 from linkml_runtime.loaders import json_loader, yaml_loader
 from oaklib import get_adapter
 from oaklib.cli import clear_cli_settings, main
@@ -1266,6 +1266,16 @@ def test_diffs(self):
             self.assertTrue(
                 any(c.about_node == "GO:0033673" for c in changes if isinstance(c, NodeChange))
             )
+            self.assertTrue(
+                any(c.subject == NUCLEUS for c in changes if isinstance(c, MappingCreation))
+            )
+            self.assertTrue(
+                any(
+                    c.about_node == CELLULAR_COMPONENT
+                    for c in changes
+                    if isinstance(c, RemoveMapping)
+                )
+            )
             catalytic_activity_changed = any(
                 c.about_node == CATALYTIC_ACTIVITY for c in changes if isinstance(c, NodeChange)
             )
diff --git a/tests/test_implementations/__init__.py b/tests/test_implementations/__init__.py
index 3446c914b..96dadce99 100644
--- a/tests/test_implementations/__init__.py
+++ b/tests/test_implementations/__init__.py
@@ -1035,6 +1035,18 @@ def test_diff(self, oi: DifferInterface, oi_modified: DifferInterface):
                 predicate="RO:0002212",
                 object="GO:0016301",
             ),
+            kgcl.RemoveMapping(
+                id=FIXED_ID,
+                about_node=CELLULAR_COMPONENT,
+                predicate="oio:hasDbXref",
+                object="NIF_Subcellular:sao1337158144",
+            ),
+            kgcl.MappingCreation(
+                id=FIXED_ID,
+                subject=NUCLEUS,
+                predicate="oio:hasDbXref",
+                object="foo:test",
+            ),
         ]
         for ch in diff:
             if isinstance(ch, list):
@@ -1070,6 +1082,18 @@ def test_diff(self, oi: DifferInterface, oi_modified: DifferInterface):
                 new_value="catalytic activity",
             ),
             kgcl.ClassCreation(id=FIXED_ID, about_node="GO:0033673"),
+            kgcl.MappingCreation(
+                id=FIXED_ID,
+                subject=CELLULAR_COMPONENT,
+                predicate="oio:hasDbXref",
+                object="NIF_Subcellular:sao1337158144",
+            ),
+            kgcl.RemoveMapping(
+                id=FIXED_ID,
+                about_node=NUCLEUS,
+                predicate="oio:hasDbXref",
+                object="foo:test",
+            ),
         ]
         rdiff = list(oi_modified.diff(oi))
         for ch in rdiff: