diff --git a/app/events/sqlalchemy.py b/app/events/sqlalchemy.py
index 256b64534c8bcc4472b803efcbb7304fc1187f95..27c8e23330c61012b5c36387515f0f4680be0490 100644
--- a/app/events/sqlalchemy.py
+++ b/app/events/sqlalchemy.py
@@ -96,9 +96,9 @@ def ressource_after_update_handler(mapper, connection, ressource):
         if not history.has_changes():
             continue
         new_value = history.added[0]
-        # DateTime attributes must be converted to a timestamp
+        # DateTime attributes must be converted to a string
         if isinstance(new_value, datetime):
-            new_value = new_value.timestamp()
+            new_value = new_value.isoformat()
         jsonpatch.append(
             {
                 'op': 'replace',
diff --git a/app/models.py b/app/models.py
index 2dc22a5e04df3b3d0417b62b8acccd383d4cad56..ba1f79557a8cacaa478616f5b634542e160981b2 100644
--- a/app/models.py
+++ b/app/models.py
@@ -157,8 +157,8 @@ class User(UserMixin, db.Model):
             'role_id': self.role_id,
             'confirmed': self.confirmed,
             'email': self.email,
-            'last_seen': self.last_seen.timestamp(),
-            'member_since': self.member_since.timestamp(),
+            'last_seen': self.last_seen.isoformat(),
+            'member_since': self.member_since.isoformat(),
             'settings': {'dark_mode': self.setting_dark_mode,
                          'job_status_mail_notifications':
                              self.setting_job_status_mail_notifications,
@@ -433,9 +433,9 @@ class Job(db.Model):
             'url': self.url,
             'id': self.id,
             'user_id': self.user_id,
-            'creation_date': self.creation_date.timestamp(),
+            'creation_date': self.creation_date.isoformat(),
             'description': self.description,
-            'end_date': self.end_date.timestamp() if self.end_date else None,
+            'end_date': self.end_date.isoformat() if self.end_date else None,
             'service': self.service,
             'service_args': self.service_args,
             'service_version': self.service_version,
@@ -557,11 +557,11 @@ class Corpus(db.Model):
             'url': self.url,
             'id': self.id,
             'user_id': self.user_id,
-            'creation_date': self.creation_date.timestamp(),
+            'creation_date': self.creation_date.isoformat(),
             'current_nr_of_tokens': self.current_nr_of_tokens,
             'description': self.description,
             'status': self.status,
-            'last_edited_date': self.last_edited_date.timestamp(),
+            'last_edited_date': self.last_edited_date.isoformat(),
             'max_nr_of_tokens': self.max_nr_of_tokens,
             'title': self.title,
         }
diff --git a/app/static/js/nopaque/RessourceDisplays/CorpusDisplay.js b/app/static/js/nopaque/RessourceDisplays/CorpusDisplay.js
index 72fbd734221215a9de6c6fee0941be234ecb6f2c..827fa02bc3a945032090dcdc0fc321b0e48e2ab9 100644
--- a/app/static/js/nopaque/RessourceDisplays/CorpusDisplay.js
+++ b/app/static/js/nopaque/RessourceDisplays/CorpusDisplay.js
@@ -91,13 +91,13 @@ class CorpusDisplay extends RessourceDisplay {
     }
   }
 
-  setCreationDate(creationDateTimestamp) {
-    let creationDate = new Date(creationDateTimestamp * 1000).toLocaleString("en-US");
+  setCreationDate(iso8601CreationDate) {
+    let creationDate = new Date(iso8601CreationDate).toLocaleString("en-US");
     for (let element of this.displayElement.querySelectorAll('.corpus-creation-date')) {this.setElement(element, creationDate);}
   }
 
-  setLastEditedDate(endDateTimestamp) {
-    let endDate = new Date(endDateTimestamp * 1000).toLocaleString("en-US");
+  setLastEditedDate(iso8601LastEditedDate) {
+    let endDate = new Date(iso8601LastEditedDate).toLocaleString("en-US");
     for (let element of this.displayElement.querySelectorAll('.corpus-end-date')) {this.setElement(element, endDate);}
   }
 }
diff --git a/app/static/js/nopaque/RessourceDisplays/JobDisplay.js b/app/static/js/nopaque/RessourceDisplays/JobDisplay.js
index a1dd36909449eb4c384ef32f9e4c8b5b4023f976..dfe4290420f50cef35af3068f4d1a5596702da34 100644
--- a/app/static/js/nopaque/RessourceDisplays/JobDisplay.js
+++ b/app/static/js/nopaque/RessourceDisplays/JobDisplay.js
@@ -63,13 +63,13 @@ class JobDisplay extends RessourceDisplay {
     }
   }
 
-  setCreationDate(creationDateTimestamp) {
-    let creationDate = new Date(creationDateTimestamp * 1000).toLocaleString("en-US");
+  setCreationDate(iso8601CreationDate) {
+    let creationDate = new Date(iso8601CreationDate).toLocaleString("en-US");
     for (let element of this.displayElement.querySelectorAll('.job-creation-date')) {this.setElement(element, creationDate);}
   }
 
-  setEndDate(endDateTimestamp) {
-    let endDate = new Date(endDateTimestamp * 1000).toLocaleString("en-US");
+  setEndDate(iso8601EndDate) {
+    let endDate = new Date(iso8601EndDate).toLocaleString("en-US");
     for (let element of this.displayElement.querySelectorAll('.job-end-date')) {this.setElement(element, endDate);}
   }