diff --git a/apiserver/bll/event/event_bll.py b/apiserver/bll/event/event_bll.py
index e6a0c36..c1350a7 100644
--- a/apiserver/bll/event/event_bll.py
+++ b/apiserver/bll/event/event_bll.py
@@ -130,7 +130,11 @@ class EventBLL(object):
             return res
 
     def add_events(
-        self, company_id, events, worker
+        self,
+        company_id: str,
+        user_id: str,
+        events: Sequence[dict],
+        worker: str,
     ) -> Tuple[int, int, dict]:
         task_ids = {}
         model_ids = {}
@@ -311,21 +315,24 @@ class EventBLL(object):
                         else:
                             errors_per_type["Error when indexing events batch"] += 1
 
+            now = datetime.utcnow()
             for model_id in used_model_ids:
                 ModelBLL.update_statistics(
                     company_id=company_id,
+                    user_id=user_id,
                     model_id=model_id,
+                    last_update=now,
                     last_iteration_max=task_iteration.get(model_id),
                     last_scalar_events=task_last_scalar_events.get(model_id),
                 )
             remaining_tasks = set()
-            now = datetime.utcnow()
             for task_id in used_task_ids:
                 # Update related tasks. For reasons of performance, we prefer to update
                 # all of them and not only those who's events were successful
                 updated = self._update_task(
                     company_id=company_id,
                     task_id=task_id,
+                    user_id=user_id,
                     now=now,
                     iter_max=task_iteration.get(task_id),
                     last_scalar_events=task_last_scalar_events.get(task_id),
@@ -336,7 +343,12 @@ class EventBLL(object):
                     continue
 
             if remaining_tasks:
-                TaskBLL.set_last_update(remaining_tasks, company_id, last_update=now)
+                TaskBLL.set_last_update(
+                    remaining_tasks,
+                    company_id=company_id,
+                    user_id=user_id,
+                    last_update=now,
+                )
 
             # this is for backwards compatibility with streaming bulk throwing exception on those
             invalid_iterations_count = errors_per_type.get(invalid_iteration_error)
@@ -466,9 +478,10 @@ class EventBLL(object):
 
     def _update_task(
         self,
-        company_id,
-        task_id,
-        now,
+        company_id: str,
+        user_id: str,
+        task_id: str,
+        now: datetime,
         iter_max=None,
         last_scalar_events=None,
         last_events=None,
@@ -484,8 +497,9 @@ class EventBLL(object):
             return False
 
         return TaskBLL.update_statistics(
-            task_id,
-            company_id,
+            task_id=task_id,
+            company_id=company_id,
+            user_id=user_id,
             last_update=now,
             last_iteration_max=iter_max,
             last_scalar_events=last_scalar_events,
diff --git a/apiserver/bll/model/__init__.py b/apiserver/bll/model/__init__.py
index 0c99ea8..3215e91 100644
--- a/apiserver/bll/model/__init__.py
+++ b/apiserver/bll/model/__init__.py
@@ -80,7 +80,14 @@ class ModelBLL:
                     id=model.task, data=task_publish_res
                 )
 
-        updated = model.update(upsert=False, ready=True, last_update=datetime.utcnow())
+        now = datetime.utcnow()
+        updated = model.update(
+            upsert=False,
+            ready=True,
+            last_update=now,
+            last_change=now,
+            last_changed_by=user_id,
+        )
         return updated, published_task
 
     @classmethod
@@ -125,6 +132,7 @@ class ModelBLL:
                                 "models.output.$[elem].model": deleted_model_id,
                                 "output.error": f"model deleted on {now.isoformat()}",
                                 "last_change": now,
+                                "last_changed_by": user_id,
                             },
                         },
                         array_filters=[{"elem.model": model_id}],
@@ -132,7 +140,9 @@ class ModelBLL:
                     )
                 else:
                     task.update(
-                        pull__models__output__model=model_id, set__last_change=now
+                        pull__models__output__model=model_id,
+                        set__last_change=now,
+                        set__last_changed_by=user_id,
                     )
 
         delete_external_artifacts = delete_external_artifacts and config.get(
@@ -167,25 +177,29 @@ class ModelBLL:
         return del_count, model
 
     @classmethod
-    def archive_model(cls, model_id: str, company_id: str):
+    def archive_model(cls, model_id: str, company_id: str, user_id: str):
         cls.get_company_model_by_id(
             company_id=company_id, model_id=model_id, only_fields=("id",)
         )
+        now = datetime.utcnow()
         archived = Model.objects(company=company_id, id=model_id).update(
             add_to_set__system_tags=EntityVisibility.archived.value,
-            last_update=datetime.utcnow(),
+            last_change=now,
+            last_changed_by=user_id,
         )
 
         return archived
 
     @classmethod
-    def unarchive_model(cls, model_id: str, company_id: str):
+    def unarchive_model(cls, model_id: str, company_id: str, user_id: str):
         cls.get_company_model_by_id(
             company_id=company_id, model_id=model_id, only_fields=("id",)
         )
+        now = datetime.utcnow()
         unarchived = Model.objects(company=company_id, id=model_id).update(
             pull__system_tags=EntityVisibility.archived.value,
-            last_update=datetime.utcnow(),
+            last_change=now,
+            last_changed_by=user_id,
         )
 
         return unarchived
@@ -218,11 +232,18 @@ class ModelBLL:
     @staticmethod
     def update_statistics(
         company_id: str,
+        user_id: str,
         model_id: str,
+        last_update: datetime = None,
         last_iteration_max: int = None,
         last_scalar_events: Dict[str, Dict[str, dict]] = None,
     ):
-        updates = {"last_update": datetime.utcnow()}
+        last_update = last_update or datetime.utcnow()
+        updates = {
+            "last_update": datetime.utcnow(),
+            "last_change": last_update,
+            "last_changed_by": user_id,
+        }
         if last_iteration_max is not None:
             updates.update(max__last_iteration=last_iteration_max)
 
diff --git a/apiserver/bll/project/project_bll.py b/apiserver/bll/project/project_bll.py
index dcaa6bf..e55bb5e 100644
--- a/apiserver/bll/project/project_bll.py
+++ b/apiserver/bll/project/project_bll.py
@@ -315,11 +315,12 @@ class ProjectBLL:
                 description="",
             )
 
-        extra = (
-            {"set__last_change": datetime.utcnow()}
-            if hasattr(entity_cls, "last_change")
-            else {}
-        )
+        extra = {}
+        if hasattr(entity_cls, "last_change"):
+            extra["set__last_change"] = datetime.utcnow()
+        if hasattr(entity_cls, "last_changed_by"):
+            extra["set__last_changed_by"] = user
+
         entity_cls.objects(company=company, id__in=ids).update(
             set__project=project, **extra
         )
diff --git a/apiserver/bll/project/project_cleanup.py b/apiserver/bll/project/project_cleanup.py
index 9f28cfa..bf3cbd1 100644
--- a/apiserver/bll/project/project_cleanup.py
+++ b/apiserver/bll/project/project_cleanup.py
@@ -185,10 +185,10 @@ def delete_project(
         res = DeleteProjectResult(disassociated_tasks=disassociated[Task])
     else:
         deleted_models, model_event_urls, model_urls = _delete_models(
-            company=company, projects=project_ids
+            company=company, user=user, projects=project_ids
         )
         deleted_tasks, task_event_urls, artifact_urls = _delete_tasks(
-            company=company, projects=project_ids
+            company=company, user=user, projects=project_ids
         )
         event_urls = task_event_urls | model_event_urls
         if delete_external_artifacts:
@@ -217,7 +217,7 @@ def delete_project(
     return res, affected
 
 
-def _delete_tasks(company: str, projects: Sequence[str]) -> Tuple[int, Set, Set]:
+def _delete_tasks(company: str, user: str, projects: Sequence[str]) -> Tuple[int, Set, Set]:
     """
     Delete only the task themselves and their non published version.
     Child models under the same project are deleted separately.
@@ -229,8 +229,17 @@ def _delete_tasks(company: str, projects: Sequence[str]) -> Tuple[int, Set, Set]
         return 0, set(), set()
 
     task_ids = {t.id for t in tasks}
-    Task.objects(parent__in=task_ids, project__nin=projects).update(parent=None)
-    Model.objects(task__in=task_ids, project__nin=projects).update(task=None)
+    now = datetime.utcnow()
+    Task.objects(parent__in=task_ids, project__nin=projects).update(
+        parent=None,
+        last_change=now,
+        last_changed_by=user,
+    )
+    Model.objects(task__in=task_ids, project__nin=projects).update(
+        task=None,
+        last_change=now,
+        last_changed_by=user,
+    )
 
     event_urls, artifact_urls = set(), set()
     for task in tasks:
@@ -253,7 +262,7 @@ def _delete_tasks(company: str, projects: Sequence[str]) -> Tuple[int, Set, Set]
 
 
 def _delete_models(
-    company: str, projects: Sequence[str]
+    company: str, user: str, projects: Sequence[str]
 ) -> Tuple[int, Set[str], Set[str]]:
     """
     Delete project models and update the tasks from other projects
@@ -287,7 +296,11 @@ def _delete_models(
                 "status": TaskStatus.published,
             },
             update={
-                "$set": {"models.output.$[elem].model": deleted, "last_change": now,}
+                "$set": {
+                    "models.output.$[elem].model": deleted,
+                    "last_change": now,
+                    "last_changed_by": user,
+                }
             },
             array_filters=[{"elem.model": {"$in": model_ids}}],
             upsert=False,
@@ -295,7 +308,11 @@ def _delete_models(
         # update unpublished tasks
         Task.objects(
             id__in=model_tasks, project__nin=projects, status__ne=TaskStatus.published,
-        ).update(pull__models__output__model__in=model_ids, set__last_change=now)
+        ).update(
+            pull__models__output__model__in=model_ids,
+            set__last_change=now,
+            set__last_changed_by=user,
+        )
 
     event_urls, model_urls = set(), set()
     for m in models:
diff --git a/apiserver/bll/task/non_responsive_tasks_watchdog.py b/apiserver/bll/task/non_responsive_tasks_watchdog.py
index bac627b..20aa83f 100644
--- a/apiserver/bll/task/non_responsive_tasks_watchdog.py
+++ b/apiserver/bll/task/non_responsive_tasks_watchdog.py
@@ -85,6 +85,7 @@ class NonResponsiveTasksWatchdog:
                     status_changed=now,
                     last_update=now,
                     last_change=now,
+                    last_changed_by="__apiserver__",
                 )
                 if updated:
                     project_ids.add(task.project)
diff --git a/apiserver/bll/task/task_bll.py b/apiserver/bll/task/task_bll.py
index 210adf1..ab6704f 100644
--- a/apiserver/bll/task/task_bll.py
+++ b/apiserver/bll/task/task_bll.py
@@ -356,6 +356,7 @@ class TaskBLL:
     def set_last_update(
         task_ids: Collection[str],
         company_id: str,
+        user_id: str,
         last_update: datetime,
         **extra_updates,
     ):
@@ -376,6 +377,7 @@ class TaskBLL:
                 upsert=False,
                 last_update=last_update,
                 last_change=last_update,
+                last_changed_by=user_id,
                 **updates,
             )
         return count
@@ -384,6 +386,7 @@ class TaskBLL:
     def update_statistics(
         task_id: str,
         company_id: str,
+        user_id: str,
         last_update: datetime = None,
         last_iteration: int = None,
         last_iteration_max: int = None,
@@ -440,6 +443,7 @@ class TaskBLL:
         ret = TaskBLL.set_last_update(
             task_ids=[task_id],
             company_id=company_id,
+            user_id=user_id,
             last_update=last_update,
             **extra_updates,
         )
diff --git a/apiserver/bll/task/task_cleanup.py b/apiserver/bll/task/task_cleanup.py
index 83f84f4..2c74003 100644
--- a/apiserver/bll/task/task_cleanup.py
+++ b/apiserver/bll/task/task_cleanup.py
@@ -222,8 +222,13 @@ def cleanup_task(
 
     deleted_task_id = f"{deleted_prefix}{task.id}"
     updated_children = 0
+    now = datetime.utcnow()
     if update_children:
-        updated_children = Task.objects(parent=task.id).update(parent=deleted_task_id)
+        updated_children = Task.objects(parent=task.id).update(
+            parent=deleted_task_id,
+            last_change=now,
+            last_changed_by=user,
+        )
 
     deleted_models = 0
     updated_models = 0
@@ -249,15 +254,25 @@ def cleanup_task(
 
             deleted_models += Model.objects(id__in=list(model_ids)).delete()
             if in_use_model_ids:
-                Model.objects(id__in=list(in_use_model_ids)).update(unset__task=1)
+                Model.objects(id__in=list(in_use_model_ids)).update(
+                    unset__task=1,
+                    set__last_change=now,
+                    set__last_changed_by=user,
+                )
             continue
 
         if update_children:
             updated_models += Model.objects(id__in=[m.id for m in models]).update(
-                task=deleted_task_id
+                task=deleted_task_id,
+                last_change=now,
+                last_changed_by=user,
             )
         else:
-            Model.objects(id__in=[m.id for m in models]).update(unset__task=1)
+            Model.objects(id__in=[m.id for m in models]).update(
+                unset__task=1,
+                set__last_change=now,
+                set__last_changed_by=user,
+            )
 
     event_bll.delete_task_events(
         task.company, task.id, allow_locked=force, async_delete=async_events_delete
diff --git a/apiserver/bll/workers/__init__.py b/apiserver/bll/workers/__init__.py
index 3f26e54..bfa6111 100644
--- a/apiserver/bll/workers/__init__.py
+++ b/apiserver/bll/workers/__init__.py
@@ -175,6 +175,7 @@ class WorkerBLL:
                         last_worker_report=now,
                         last_update=now,
                         last_change=now,
+                        last_changed_by=user_id,
                     )
                     # modify(new=True, ...) returns the modified object
                     task = Task.objects(**query).modify(new=True, **update)
diff --git a/apiserver/database/model/base.py b/apiserver/database/model/base.py
index 8f5eeb3..a5e32a0 100644
--- a/apiserver/database/model/base.py
+++ b/apiserver/database/model/base.py
@@ -1,5 +1,6 @@
 import re
 from collections import namedtuple, defaultdict
+from datetime import datetime
 from functools import reduce, partial
 from typing import (
     Collection,
@@ -147,8 +148,7 @@ class GetMixin(PropsMixin):
         }
         default_operator = Q.OR
         mongo_modifiers = {
-            # not_all modifier currently not supported due to the backwards compatibility
-            Q.AND: {True: "all", False: "nin"},
+            Q.AND: {True: "all", False: "not__all"},
             Q.OR: {True: "in", False: "nin"},
         }
 
@@ -1234,25 +1234,31 @@ class DbModelMixin(GetMixin, ProperDictMixin, UpdateMixin):
     def set_public(
         cls: Type[Document],
         company_id: str,
+        user_id: str,
         ids: Sequence[str],
         invalid_cls: Type[BaseError],
         enabled: bool = True,
     ):
         if enabled:
             items = list(cls.objects(id__in=ids, company=company_id).only("id"))
-            update = dict(set__company_origin=company_id, set__company="")
+            update: dict = dict(set__company_origin=company_id, set__company="")
         else:
             items = list(
                 cls.objects(
                     id__in=ids, company__in=(None, ""), company_origin=company_id
                 ).only("id")
             )
-            update = dict(set__company=company_id, unset__company_origin=1)
+            update: dict = dict(set__company=company_id, unset__company_origin=1)
 
         if len(items) < len(ids):
             missing = tuple(set(ids).difference(i.id for i in items))
             raise invalid_cls(ids=missing)
 
+        if hasattr(cls, "last_change"):
+            update["set__last_change"] = datetime.utcnow()
+        if hasattr(cls, "last_changed_by"):
+            update["set__last_changed_by"] = user_id
+
         return {"updated": cls.objects(id__in=ids).update(**update)}
 
 
diff --git a/apiserver/database/model/model.py b/apiserver/database/model/model.py
index adf0836..7516312 100644
--- a/apiserver/database/model/model.py
+++ b/apiserver/database/model/model.py
@@ -90,6 +90,8 @@ class Model(AttributedDocument):
     labels = ModelLabels()
     ready = BooleanField(required=True)
     last_update = DateTimeField()
+    last_change = DateTimeField()
+    last_changed_by = StringField()
     ui_cache = SafeDictField(
         default=dict, user_set_allowed=True, exclude_by_default=True
     )
diff --git a/apiserver/mongo/initialize/pre_populate.py b/apiserver/mongo/initialize/pre_populate.py
index d7a68dc..7860e65 100644
--- a/apiserver/mongo/initialize/pre_populate.py
+++ b/apiserver/mongo/initialize/pre_populate.py
@@ -960,7 +960,7 @@ class PrePopulate:
             return tasks
 
     @classmethod
-    def _import_events(cls, f: IO[bytes], company_id: str, _, task_id: str):
+    def _import_events(cls, f: IO[bytes], company_id: str, user_id: str, task_id: str):
         print(f"Writing events for task {task_id} into database")
         for events_chunk in chunked_iter(cls.json_lines(f), 1000):
             events = [json.loads(item) for item in events_chunk]
@@ -969,5 +969,8 @@ class PrePopulate:
                 ev["company_id"] = company_id
                 ev["allow_locked"] = True
             cls.event_bll.add_events(
-                company_id, events=events, worker=""
+                company_id=company_id,
+                user_id=user_id,
+                events=events,
+                worker="",
             )
diff --git a/apiserver/services/events.py b/apiserver/services/events.py
index c17ea52..4b703ec 100644
--- a/apiserver/services/events.py
+++ b/apiserver/services/events.py
@@ -71,7 +71,12 @@ def _assert_task_or_model_exists(
 @endpoint("events.add")
 def add(call: APICall, company_id, _):
     data = call.data.copy()
-    added, err_count, err_info = event_bll.add_events(company_id, [data], call.worker)
+    added, err_count, err_info = event_bll.add_events(
+        company_id=company_id,
+        user_id=call.identity.user,
+        events=[data],
+        worker=call.worker,
+    )
     call.result.data = dict(added=added, errors=err_count, errors_info=err_info)
 
 
@@ -82,9 +87,10 @@ def add_batch(call: APICall, company_id, _):
         raise errors.bad_request.BatchContainsNoItems()
 
     added, err_count, err_info = event_bll.add_events(
-        company_id,
-        events,
-        call.worker,
+        company_id=company_id,
+        user_id=call.identity.user,
+        events=events,
+        worker=call.worker,
     )
     call.result.data = dict(added=added, errors=err_count, errors_info=err_info)
 
diff --git a/apiserver/services/models.py b/apiserver/services/models.py
index cdc4d7b..258f57a 100644
--- a/apiserver/services/models.py
+++ b/apiserver/services/models.py
@@ -76,7 +76,9 @@ def get_by_id(call: APICall, company_id, _):
     )
     if not models:
         raise errors.bad_request.InvalidModelId(
-            "no such public or company model", id=model_id, company=company_id,
+            "no such public or company model",
+            id=model_id,
+            company=company_id,
         )
     conform_model_data(call, models[0])
     call.result.data = {"model": models[0]}
@@ -102,7 +104,9 @@ def get_by_task_id(call: APICall, company_id, _):
     ).first()
     if not model:
         raise errors.bad_request.InvalidModelId(
-            "no such public or company model", id=model_id, company=company_id,
+            "no such public or company model",
+            id=model_id,
+            company=company_id,
         )
     model_dict = model.to_proper_dict()
     conform_model_data(call, model_dict)
@@ -128,7 +132,10 @@ def get_all_ex(call: APICall, company_id, request: ModelsGetRequest):
         return
 
     model_ids = {model["id"] for model in models}
-    stats = ModelBLL.get_model_stats(company=company_id, model_ids=list(model_ids),)
+    stats = ModelBLL.get_model_stats(
+        company=company_id,
+        model_ids=list(model_ids),
+    )
 
     for model in models:
         model["stats"] = stats.get(model["id"])
@@ -220,7 +227,9 @@ def _update_cached_tags(company: str, project: str, fields: dict):
 
 def _reset_cached_tags(company: str, projects: Sequence[str]):
     org_bll.reset_tags(
-        company, Tags.Model, projects=projects,
+        company,
+        Tags.Model,
+        projects=projects,
     )
 
 
@@ -283,6 +292,8 @@ def update_for_task(call: APICall, company_id, _):
             id=database.utils.id(),
             created=now,
             last_update=now,
+            last_change=now,
+            last_changed_by=call.identity.user,
             user=call.identity.user,
             company=company_id,
             project=task.project,
@@ -301,6 +312,7 @@ def update_for_task(call: APICall, company_id, _):
     TaskBLL.update_statistics(
         task_id=task_id,
         company_id=company_id,
+        user_id=call.identity.user,
         last_iteration_max=iteration,
         models__output=[
             ModelItem(
@@ -320,7 +332,6 @@ def update_for_task(call: APICall, company_id, _):
     response_data_model=CreateModelResponse,
 )
 def create(call: APICall, company_id, req_model: CreateModelRequest):
-
     if req_model.public:
         company_id = ""
 
@@ -345,6 +356,8 @@ def create(call: APICall, company_id, req_model: CreateModelRequest):
         company=company_id,
         created=now,
         last_update=now,
+        last_change=now,
+        last_changed_by=call.identity.user,
         **fields,
     )
     model.save()
@@ -414,12 +427,20 @@ def edit(call: APICall, company_id, _):
     task_id = model.task or fields.get("task")
     if task_id and iteration is not None:
         TaskBLL.update_statistics(
-            task_id=task_id, company_id=company_id, last_iteration_max=iteration,
+            task_id=task_id,
+            company_id=company_id,
+            user_id=call.identity.user,
+            last_iteration_max=iteration,
         )
 
     if fields:
+        now = datetime.utcnow()
+        fields.update(
+            last_change=now,
+            last_changed_by=call.identity.user,
+        )
         if any(uf in fields for uf in last_update_fields):
-            fields.update(last_update=datetime.utcnow())
+            fields.update(last_update=now)
 
         updated = model.update(upsert=False, **fields)
         if updated:
@@ -445,13 +466,25 @@ def _update_model(call: APICall, company_id, model_id=None):
     iteration = data.get("iteration")
     if task_id and iteration is not None:
         TaskBLL.update_statistics(
-            task_id=task_id, company_id=company_id, last_iteration_max=iteration,
+            task_id=task_id,
+            company_id=company_id,
+            user_id=call.identity.user,
+            last_iteration_max=iteration,
         )
 
-    updated_count, updated_fields = Model.safe_update(company_id, model.id, data)
+    now = datetime.utcnow()
+    updated_count, updated_fields = Model.safe_update(
+        company_id,
+        model.id,
+        data,
+        injected_update=dict(
+            last_change=now,
+            last_changed_by=call.identity.user,
+        ),
+    )
     if updated_count:
         if any(uf in updated_fields for uf in last_update_fields):
-            model.update(upsert=False, last_update=datetime.utcnow())
+            model.update(upsert=False, last_update=now)
 
         new_project = updated_fields.get("project", model.project)
         if new_project != model.project:
@@ -573,7 +606,10 @@ def delete(call: APICall, company_id, request: ModelsDeleteManyRequest):
 )
 def archive_many(call: APICall, company_id, request: BatchRequest):
     results, failures = run_batch_operation(
-        func=partial(ModelBLL.archive_model, company_id=company_id), ids=request.ids,
+        func=partial(
+            ModelBLL.archive_model, company_id=company_id, user_id=call.identity.user
+        ),
+        ids=request.ids,
     )
     call.result.data_model = BatchResponse(
         succeeded=[dict(id=_id, archived=bool(archived)) for _id, archived in results],
@@ -588,7 +624,8 @@ def archive_many(call: APICall, company_id, request: BatchRequest):
 )
 def unarchive_many(call: APICall, company_id, request: BatchRequest):
     results, failures = run_batch_operation(
-        func=partial(ModelBLL.unarchive_model, company_id=company_id), ids=request.ids,
+        func=partial(ModelBLL.unarchive_model, company_id=company_id, user_id=call.identity.user),
+        ids=request.ids,
     )
     call.result.data_model = BatchResponse(
         succeeded=[
@@ -601,7 +638,11 @@ def unarchive_many(call: APICall, company_id, request: BatchRequest):
 @endpoint("models.make_public", min_version="2.9", request_data_model=MakePublicRequest)
 def make_public(call: APICall, company_id, request: MakePublicRequest):
     call.result.data = Model.set_public(
-        company_id, ids=request.ids, invalid_cls=InvalidModelId, enabled=True
+        company_id=company_id,
+        user_id=call.identity.user,
+        ids=request.ids,
+        invalid_cls=InvalidModelId,
+        enabled=True,
     )
 
 
@@ -610,7 +651,11 @@ def make_public(call: APICall, company_id, request: MakePublicRequest):
 )
 def make_public(call: APICall, company_id, request: MakePublicRequest):
     call.result.data = Model.set_public(
-        company_id, request.ids, invalid_cls=InvalidModelId, enabled=False
+        company_id=company_id,
+        user_id=call.identity.user,
+        ids=request.ids,
+        invalid_cls=InvalidModelId,
+        enabled=False,
     )
 
 
@@ -635,28 +680,36 @@ def move(call: APICall, company_id: str, request: MoveRequest):
 
 @endpoint("models.add_or_update_metadata", min_version="2.13")
 def add_or_update_metadata(
-    _: APICall, company_id: str, request: AddOrUpdateMetadataRequest
+    call: APICall, company_id: str, request: AddOrUpdateMetadataRequest
 ):
     model_id = request.model
     model = ModelBLL.get_company_model_by_id(company_id=company_id, model_id=model_id)
+    now = datetime.utcnow()
     return {
         "updated": Metadata.edit_metadata(
             model,
             items=request.metadata,
             replace_metadata=request.replace_metadata,
-            last_update=datetime.utcnow(),
+            last_update=now,
+            last_change=now,
+            last_changed_by=call.identity.user,
         )
     }
 
 
 @endpoint("models.delete_metadata", min_version="2.13")
-def delete_metadata(_: APICall, company_id: str, request: DeleteMetadataRequest):
+def delete_metadata(call: APICall, company_id: str, request: DeleteMetadataRequest):
     model_id = request.model
     model = ModelBLL.get_company_model_by_id(
         company_id=company_id, model_id=model_id, only_fields=("id",)
     )
+    now = datetime.utcnow()
     return {
         "updated": Metadata.delete_metadata(
-            model, keys=request.keys, last_update=datetime.utcnow()
+            model,
+            keys=request.keys,
+            last_update=now,
+            last_change=now,
+            last_changed_by=call.identity.user,
         )
     }
diff --git a/apiserver/services/projects.py b/apiserver/services/projects.py
index 858ab39..965c360 100644
--- a/apiserver/services/projects.py
+++ b/apiserver/services/projects.py
@@ -506,7 +506,11 @@ def get_tags(call: APICall, company, request: ProjectTagsRequest):
 )
 def make_public(call: APICall, company_id, request: MakePublicRequest):
     call.result.data = Project.set_public(
-        company_id, ids=request.ids, invalid_cls=InvalidProjectId, enabled=True
+        company_id=company_id,
+        user_id=call.identity.user,
+        ids=request.ids,
+        invalid_cls=InvalidProjectId,
+        enabled=True,
     )
 
 
@@ -515,7 +519,11 @@ def make_public(call: APICall, company_id, request: MakePublicRequest):
 )
 def make_public(call: APICall, company_id, request: MakePublicRequest):
     call.result.data = Project.set_public(
-        company_id, ids=request.ids, invalid_cls=InvalidProjectId, enabled=False
+        company_id=company_id,
+        user_id=call.identity.user,
+        ids=request.ids,
+        invalid_cls=InvalidProjectId,
+        enabled=False,
     )
 
 
diff --git a/apiserver/services/tasks.py b/apiserver/services/tasks.py
index fef39b2..78a7b87 100644
--- a/apiserver/services/tasks.py
+++ b/apiserver/services/tasks.py
@@ -1232,9 +1232,12 @@ def completed(call: APICall, company_id, request: CompletedRequest):
 
 
 @endpoint("tasks.ping", request_data_model=PingRequest)
-def ping(_, company_id, request: PingRequest):
+def ping(call: APICall, company_id, request: PingRequest):
     TaskBLL.set_last_update(
-        task_ids=[request.task], company_id=company_id, last_update=datetime.utcnow()
+        task_ids=[request.task],
+        company_id=company_id,
+        user_id=call.identity.user,
+        last_update=datetime.utcnow(),
     )
 
 
@@ -1277,14 +1280,22 @@ def delete_artifacts(call: APICall, company_id, request: DeleteArtifactsRequest)
 @endpoint("tasks.make_public", min_version="2.9", request_data_model=MakePublicRequest)
 def make_public(call: APICall, company_id, request: MakePublicRequest):
     call.result.data = Task.set_public(
-        company_id, request.ids, invalid_cls=InvalidTaskId, enabled=True
+        company_id=company_id,
+        user_id=call.identity.user,
+        ids=request.ids,
+        invalid_cls=InvalidTaskId,
+        enabled=True,
     )
 
 
 @endpoint("tasks.make_private", min_version="2.9", request_data_model=MakePublicRequest)
 def make_public(call: APICall, company_id, request: MakePublicRequest):
     call.result.data = Task.set_public(
-        company_id, request.ids, invalid_cls=InvalidTaskId, enabled=False
+        company_id=company_id,
+        user_id=call.identity.user,
+        ids=request.ids,
+        invalid_cls=InvalidTaskId,
+        enabled=False,
     )
 
 
@@ -1315,7 +1326,7 @@ def move(call: APICall, company_id: str, request: MoveRequest):
 
 
 @endpoint("tasks.add_or_update_model", min_version="2.13")
-def add_or_update_model(_: APICall, company_id: str, request: AddUpdateModelRequest):
+def add_or_update_model(call: APICall, company_id: str, request: AddUpdateModelRequest):
     get_task_for_update(company_id=company_id, task_id=request.task, force=True)
 
     models_field = f"models__{request.type}"
@@ -1326,6 +1337,7 @@ def add_or_update_model(_: APICall, company_id: str, request: AddUpdateModelRequ
     updated = TaskBLL.update_statistics(
         task_id=request.task,
         company_id=company_id,
+        user_id=call.identity.user,
         last_iteration_max=request.iteration,
         **({f"push__{models_field}": model} if not updated else {}),
     )