diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2998de545..f96a29355 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ and the versioning aims to respect [Semantic Versioning](http://semver.org/spec/
 - product (#1912)
 - term tracker annotation (#1913)
 - licence provider, licensee, has licence provider, permits (#1925)
+- has aggregation type, has time stamp alignment (#1944)
 
 ### Changed
 - gams -> General Algebraic Modeling System (#1889)
@@ -34,6 +35,7 @@ and the versioning aims to respect [Semantic Versioning](http://semver.org/spec/
 - is traded at, trades (#1912)
 - replace term tracker item with term tracker annotation (#1922, #1923)
 - replace has bearer with characteristic of (#1928)
+- time stamp (#1944)
 
 ### Obsoletion
 - economic value, has economic value, economic value (#1931)
diff --git a/src/ontology/edits/oeo-model.omn b/src/ontology/edits/oeo-model.omn
index a18960f67..4d27e6ec6 100644
--- a/src/ontology/edits/oeo-model.omn
+++ b/src/ontology/edits/oeo-model.omn
@@ -89,7 +89,7 @@ ObjectProperty: <http://purl.obolibrary.org/obo/BFO_0000051>
     
 ObjectProperty: <http://purl.obolibrary.org/obo/IAO_0000136>
 
-
+    
 ObjectProperty: <http://purl.obolibrary.org/obo/RO_0000052>
 
     
@@ -526,6 +526,26 @@ ObjectProperty: OEO_00140164
         OEO_00000274
     
     
+ObjectProperty: OEO_00390023
+
+    Annotations: 
+        OEO_00020426 "Added
+issue: https://github.com/OpenEnergyPlatform/ontology/issues/1901
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1944",
+        <http://purl.obolibrary.org/obo/IAO_0000115> "A relation between a data item or data set and an aggregation type that indicates the method of data aggregation applied to the data set.",
+        rdfs:label "has aggregation type"@en
+    
+    
+ObjectProperty: OEO_00390024
+
+    Annotations: 
+        OEO_00020426 "Added
+issue: https://github.com/OpenEnergyPlatform/ontology/issues/1901
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1944",
+        <http://purl.obolibrary.org/obo/IAO_0000115> "A relation between a time stamp or time series and a time stamp alignment that indicates the position of the time stamps that refer to the time step(s).",
+        rdfs:label "has time stamp alignment"@en
+    
+    
 ObjectProperty: owl:topObjectProperty
 
     
@@ -3142,8 +3162,12 @@ pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1652
 
 reclassify as data descriptor
 issue: https://github.com/OpenEnergyPlatform/ontology/issues/1536
-pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1853",
-        <http://purl.obolibrary.org/obo/IAO_0000115> "A time stamp is a data descriptor that is used to describe a zero-dimensional temporal region, or a data item that is related to a zero-dimensional temporal region, e.g. a time stamped measurement datum.",
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1853
+
+update definition
+issue: https://github.com/OpenEnergyPlatform/ontology/issues/1901
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1944",
+        <http://purl.obolibrary.org/obo/IAO_0000115> "A time stamp is a data descriptor that is used to describe either a temporal region or a data item that is related to a temporal region, e.g. a time stamped measurement datum. If the time stamp refers to a time step/one-dimensional temporal region, the indication of a time stamp alignment is required",
         <http://purl.obolibrary.org/obo/IAO_0000118> "Zeitstempel"@de,
         rdfs:label "time stamp"@en