diff --git a/server/szurubooru/api/comment_api.py b/server/szurubooru/api/comment_api.py
index 08fd09c4..51058160 100644
--- a/server/szurubooru/api/comment_api.py
+++ b/server/szurubooru/api/comment_api.py
@@ -1,7 +1,7 @@
 import datetime
 from szurubooru import search
-from szurubooru.func import auth, comments, posts, scores, util
 from szurubooru.rest import routes
+from szurubooru.func import auth, comments, posts, scores, util, versions
 
 
 _search_executor = search.Executor(search.configs.CommentSearchConfig())
@@ -43,12 +43,12 @@ def get_comment(ctx, params):
 @routes.put('/comment/(?P<comment_id>[^/]+)/?')
 def update_comment(ctx, params):
     comment = comments.get_comment_by_id(params['comment_id'])
-    util.verify_version(comment, ctx)
+    versions.verify_version(comment, ctx)
+    versions.bump_version(comment)
     infix = 'own' if ctx.user.user_id == comment.user_id else 'any'
     text = ctx.get_param_as_string('text', required=True)
     auth.verify_privilege(ctx.user, 'comments:edit:%s' % infix)
     comments.update_comment_text(comment, text)
-    util.bump_version(comment)
     comment.last_edit_time = datetime.datetime.utcnow()
     ctx.session.commit()
     return _serialize(ctx, comment)
@@ -57,7 +57,7 @@ def update_comment(ctx, params):
 @routes.delete('/comment/(?P<comment_id>[^/]+)/?')
 def delete_comment(ctx, params):
     comment = comments.get_comment_by_id(params['comment_id'])
-    util.verify_version(comment, ctx)
+    versions.verify_version(comment, ctx)
     infix = 'own' if ctx.user.user_id == comment.user_id else 'any'
     auth.verify_privilege(ctx.user, 'comments:delete:%s' % infix)
     ctx.session.delete(comment)
diff --git a/server/szurubooru/api/info_api.py b/server/szurubooru/api/info_api.py
index a5485546..8e74cb72 100644
--- a/server/szurubooru/api/info_api.py
+++ b/server/szurubooru/api/info_api.py
@@ -1,8 +1,8 @@
 import datetime
 import os
 from szurubooru import config
-from szurubooru.func import posts, users, util
 from szurubooru.rest import routes
+from szurubooru.func import posts, users, util
 
 
 _cache_time = None
diff --git a/server/szurubooru/api/password_reset_api.py b/server/szurubooru/api/password_reset_api.py
index fbc4ba4d..7e5864c9 100644
--- a/server/szurubooru/api/password_reset_api.py
+++ b/server/szurubooru/api/password_reset_api.py
@@ -1,6 +1,6 @@
 from szurubooru import config, errors
-from szurubooru.func import auth, mailer, users, util
 from szurubooru.rest import routes
+from szurubooru.func import auth, mailer, users, versions
 
 
 MAIL_SUBJECT = 'Password reset for {name}'
@@ -40,6 +40,6 @@ def finish_password_reset(ctx, params):
     if token != good_token:
         raise errors.ValidationError('Invalid password reset token.')
     new_password = users.reset_user_password(user)
-    util.bump_version(user)
+    versions.bump_version(user)
     ctx.session.commit()
     return {'password': new_password}
diff --git a/server/szurubooru/api/post_api.py b/server/szurubooru/api/post_api.py
index e800bd54..53bbcd26 100644
--- a/server/szurubooru/api/post_api.py
+++ b/server/szurubooru/api/post_api.py
@@ -2,7 +2,7 @@ import datetime
 from szurubooru import search
 from szurubooru.rest import routes
 from szurubooru.func import (
-    auth, tags, posts, snapshots, favorites, scores, util)
+    auth, tags, posts, snapshots, favorites, scores, util, versions)
 
 
 _search_executor = search.Executor(search.configs.PostSearchConfig())
@@ -68,7 +68,8 @@ def get_post(ctx, params):
 @routes.put('/post/(?P<post_id>[^/]+)/?')
 def update_post(ctx, params):
     post = posts.get_post_by_id(params['post_id'])
-    util.verify_version(post, ctx)
+    versions.verify_version(post, ctx)
+    versions.bump_version(post)
     if ctx.has_file('content'):
         auth.verify_privilege(ctx.user, 'posts:edit:content')
         posts.update_post_content(post, ctx.get_file('content'))
@@ -97,7 +98,6 @@ def update_post(ctx, params):
     if ctx.has_file('thumbnail'):
         auth.verify_privilege(ctx.user, 'posts:edit:thumbnail')
         posts.update_post_thumbnail(post, ctx.get_file('thumbnail'))
-    util.bump_version(post)
     post.last_edit_time = datetime.datetime.utcnow()
     ctx.session.flush()
     snapshots.save_entity_modification(post, ctx.user)
@@ -110,7 +110,7 @@ def update_post(ctx, params):
 def delete_post(ctx, params):
     auth.verify_privilege(ctx.user, 'posts:delete')
     post = posts.get_post_by_id(params['post_id'])
-    util.verify_version(post, ctx)
+    versions.verify_version(post, ctx)
     snapshots.save_entity_deletion(post, ctx.user)
     posts.delete(post)
     ctx.session.commit()
diff --git a/server/szurubooru/api/snapshot_api.py b/server/szurubooru/api/snapshot_api.py
index bf6eba86..1a5f5896 100644
--- a/server/szurubooru/api/snapshot_api.py
+++ b/server/szurubooru/api/snapshot_api.py
@@ -1,6 +1,6 @@
 from szurubooru import search
-from szurubooru.func import auth, snapshots
 from szurubooru.rest import routes
+from szurubooru.func import auth, snapshots
 
 
 _search_executor = search.Executor(search.configs.SnapshotSearchConfig())
diff --git a/server/szurubooru/api/tag_api.py b/server/szurubooru/api/tag_api.py
index 630cf19b..4daf7e5a 100644
--- a/server/szurubooru/api/tag_api.py
+++ b/server/szurubooru/api/tag_api.py
@@ -1,7 +1,7 @@
 import datetime
 from szurubooru import db, search
-from szurubooru.func import auth, tags, util, snapshots
 from szurubooru.rest import routes
+from szurubooru.func import auth, tags, snapshots, util, versions
 
 
 _search_executor = search.Executor(search.configs.TagSearchConfig())
@@ -66,7 +66,8 @@ def get_tag(ctx, params):
 @routes.put('/tag/(?P<tag_name>[^/]+)/?')
 def update_tag(ctx, params):
     tag = tags.get_tag_by_name(params['tag_name'])
-    util.verify_version(tag, ctx)
+    versions.verify_version(tag, ctx)
+    versions.bump_version(tag)
     if ctx.has_param('names'):
         auth.verify_privilege(ctx.user, 'tags:edit:names')
         tags.update_tag_names(tag, ctx.get_param_as_list('names'))
@@ -88,7 +89,6 @@ def update_tag(ctx, params):
         implications = ctx.get_param_as_list('implications')
         _create_if_needed(implications, ctx.user)
         tags.update_tag_implications(tag, implications)
-    util.bump_version(tag)
     tag.last_edit_time = datetime.datetime.utcnow()
     ctx.session.flush()
     snapshots.save_entity_modification(tag, ctx.user)
@@ -100,7 +100,7 @@ def update_tag(ctx, params):
 @routes.delete('/tag/(?P<tag_name>[^/]+)/?')
 def delete_tag(ctx, params):
     tag = tags.get_tag_by_name(params['tag_name'])
-    util.verify_version(tag, ctx)
+    versions.verify_version(tag, ctx)
     auth.verify_privilege(ctx.user, 'tags:delete')
     snapshots.save_entity_deletion(tag, ctx.user)
     tags.delete(tag)
@@ -115,12 +115,12 @@ def merge_tags(ctx, _params=None):
     target_tag_name = ctx.get_param_as_string('mergeTo', required=True) or ''
     source_tag = tags.get_tag_by_name(source_tag_name)
     target_tag = tags.get_tag_by_name(target_tag_name)
-    util.verify_version(source_tag, ctx, 'removeVersion')
-    util.verify_version(target_tag, ctx, 'mergeToVersion')
+    versions.verify_version(source_tag, ctx, 'removeVersion')
+    versions.verify_version(target_tag, ctx, 'mergeToVersion')
+    versions.bump_version(target_tag)
     auth.verify_privilege(ctx.user, 'tags:merge')
     tags.merge_tags(source_tag, target_tag)
     snapshots.save_entity_deletion(source_tag, ctx.user)
-    util.bump_version(target_tag)
     ctx.session.commit()
     tags.export_to_json()
     return _serialize(ctx, target_tag)
diff --git a/server/szurubooru/api/tag_category_api.py b/server/szurubooru/api/tag_category_api.py
index fbd25530..27efb1c9 100644
--- a/server/szurubooru/api/tag_category_api.py
+++ b/server/szurubooru/api/tag_category_api.py
@@ -1,5 +1,6 @@
 from szurubooru.rest import routes
-from szurubooru.func import auth, tags, tag_categories, util, snapshots
+from szurubooru.func import (
+    auth, tags, tag_categories, snapshots, util, versions)
 
 
 def _serialize(ctx, category):
@@ -40,7 +41,8 @@ def get_tag_category(ctx, params):
 @routes.put('/tag-category/(?P<category_name>[^/]+)/?')
 def update_tag_category(ctx, params):
     category = tag_categories.get_category_by_name(params['category_name'])
-    util.verify_version(category, ctx)
+    versions.verify_version(category, ctx)
+    versions.bump_version(category)
     if ctx.has_param('name'):
         auth.verify_privilege(ctx.user, 'tag_categories:edit:name')
         tag_categories.update_category_name(
@@ -49,7 +51,6 @@ def update_tag_category(ctx, params):
         auth.verify_privilege(ctx.user, 'tag_categories:edit:color')
         tag_categories.update_category_color(
             category, ctx.get_param_as_string('color'))
-    util.bump_version(category)
     ctx.session.flush()
     snapshots.save_entity_modification(category, ctx.user)
     ctx.session.commit()
@@ -60,7 +61,7 @@ def update_tag_category(ctx, params):
 @routes.delete('/tag-category/(?P<category_name>[^/]+)/?')
 def delete_tag_category(ctx, params):
     category = tag_categories.get_category_by_name(params['category_name'])
-    util.verify_version(category, ctx)
+    versions.verify_version(category, ctx)
     auth.verify_privilege(ctx.user, 'tag_categories:delete')
     tag_categories.delete_category(category)
     snapshots.save_entity_deletion(category, ctx.user)
diff --git a/server/szurubooru/api/user_api.py b/server/szurubooru/api/user_api.py
index aa99c42f..187e4686 100644
--- a/server/szurubooru/api/user_api.py
+++ b/server/szurubooru/api/user_api.py
@@ -1,6 +1,6 @@
 from szurubooru import search
-from szurubooru.func import auth, users, util
 from szurubooru.rest import routes
+from szurubooru.func import auth, users, util, versions
 
 
 _search_executor = search.Executor(search.configs.UserSearchConfig())
@@ -52,7 +52,8 @@ def get_user(ctx, params):
 @routes.put('/user/(?P<user_name>[^/]+)/?')
 def update_user(ctx, params):
     user = users.get_user_by_name(params['user_name'])
-    util.verify_version(user, ctx)
+    versions.verify_version(user, ctx)
+    versions.bump_version(user)
     infix = 'self' if ctx.user.user_id == user.user_id else 'any'
     if ctx.has_param('name'):
         auth.verify_privilege(ctx.user, 'users:edit:%s:name' % infix)
@@ -74,7 +75,6 @@ def update_user(ctx, params):
             user,
             ctx.get_param_as_string('avatarStyle'),
             ctx.get_file('avatar'))
-    util.bump_version(user)
     ctx.session.commit()
     return _serialize(ctx, user)
 
@@ -82,7 +82,7 @@ def update_user(ctx, params):
 @routes.delete('/user/(?P<user_name>[^/]+)/?')
 def delete_user(ctx, params):
     user = users.get_user_by_name(params['user_name'])
-    util.verify_version(user, ctx)
+    versions.verify_version(user, ctx)
     infix = 'self' if ctx.user.user_id == user.user_id else 'any'
     auth.verify_privilege(ctx.user, 'users:delete:%s' % infix)
     ctx.session.delete(user)
diff --git a/server/szurubooru/db/comment.py b/server/szurubooru/db/comment.py
index 05298282..bbb8b189 100644
--- a/server/szurubooru/db/comment.py
+++ b/server/szurubooru/db/comment.py
@@ -48,3 +48,8 @@ class Comment(Base):
             .query(func.sum(CommentScore.score)) \
             .filter(CommentScore.comment_id == self.comment_id) \
             .one()[0] or 0
+
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+    }
diff --git a/server/szurubooru/db/post.py b/server/szurubooru/db/post.py
index 5529e49d..741e581c 100644
--- a/server/szurubooru/db/post.py
+++ b/server/szurubooru/db/post.py
@@ -237,3 +237,8 @@ class Post(Base):
             (PostRelation.parent_id == post_id)
             | (PostRelation.child_id == post_id))
         .correlate_except(PostRelation))
+
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+    }
diff --git a/server/szurubooru/db/tag.py b/server/szurubooru/db/tag.py
index faa6e68d..2bdac536 100644
--- a/server/szurubooru/db/tag.py
+++ b/server/szurubooru/db/tag.py
@@ -115,3 +115,8 @@ class Tag(Base):
             .where(TagImplication.parent_id == tag_id)
             .as_scalar(),
         deferred=True)
+
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+    }
diff --git a/server/szurubooru/db/tag_category.py b/server/szurubooru/db/tag_category.py
index cb1d9328..907910ba 100644
--- a/server/szurubooru/db/tag_category.py
+++ b/server/szurubooru/db/tag_category.py
@@ -21,3 +21,8 @@ class TagCategory(Base):
         select([func.count('Tag.tag_id')])
         .where(Tag.category_id == tag_category_id)
         .correlate_except(table('Tag')))
+
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+    }
diff --git a/server/szurubooru/db/user.py b/server/szurubooru/db/user.py
index f6b9ceb2..082adcff 100644
--- a/server/szurubooru/db/user.py
+++ b/server/szurubooru/db/user.py
@@ -75,3 +75,8 @@ class User(Base):
             .filter(PostScore.user_id == self.user_id)
             .filter(PostScore.score == -1)
             .one()[0] or 0)
+
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+    }
diff --git a/server/szurubooru/facade.py b/server/szurubooru/facade.py
index ad1516c6..69bc6b99 100644
--- a/server/szurubooru/facade.py
+++ b/server/szurubooru/facade.py
@@ -3,6 +3,7 @@
 import os
 import logging
 import coloredlogs
+import sqlalchemy.orm.exc
 from szurubooru import config, errors, rest
 # pylint: disable=unused-import
 from szurubooru import api, middleware
@@ -38,6 +39,11 @@ def _on_processing_error(ex):
         title='Processing error', description=str(ex))
 
 
+def _on_stale_data_error(_ex):
+    raise rest.errors.HttpConflict(
+        'Someone else modified this in the meantime. Please try again.')
+
+
 def validate_config():
     '''
     Check whether config doesn't contain errors that might prove
@@ -83,5 +89,6 @@ def create_app():
     rest.errors.handle(errors.IntegrityError, _on_integrity_error)
     rest.errors.handle(errors.NotFoundError, _on_not_found_error)
     rest.errors.handle(errors.ProcessingError, _on_processing_error)
+    rest.errors.handle(sqlalchemy.orm.exc.StaleDataError, _on_stale_data_error)
 
     return rest.application
diff --git a/server/szurubooru/func/util.py b/server/szurubooru/func/util.py
index 8a1e6c97..32e36a66 100644
--- a/server/szurubooru/func/util.py
+++ b/server/szurubooru/func/util.py
@@ -154,16 +154,3 @@ def value_exceeds_column_size(value, column):
     if max_length is None:
         return False
     return len(value) > max_length
-
-
-def verify_version(entity, context, field_name='version'):
-    actual_version = context.get_param_as_int(field_name, required=True)
-    expected_version = entity.version
-    if actual_version != expected_version:
-        raise errors.InvalidParameterError(
-            'Someone else modified this in the meantime. ' +
-            'Please try again.')
-
-
-def bump_version(entity):
-    entity.version += 1
diff --git a/server/szurubooru/func/versions.py b/server/szurubooru/func/versions.py
new file mode 100644
index 00000000..d38130ac
--- /dev/null
+++ b/server/szurubooru/func/versions.py
@@ -0,0 +1,14 @@
+from szurubooru import errors
+
+
+def verify_version(entity, context, field_name='version'):
+    actual_version = context.get_param_as_int(field_name, required=True)
+    expected_version = entity.version
+    if actual_version != expected_version:
+        raise errors.InvalidParameterError(
+            'Someone else modified this in the meantime. ' +
+            'Please try again.')
+
+
+def bump_version(entity):
+    entity.version = entity.version + 1
diff --git a/server/szurubooru/tests/api/test_tag_updating.py b/server/szurubooru/tests/api/test_tag_updating.py
index dbb8b803..81f195b9 100644
--- a/server/szurubooru/tests/api/test_tag_updating.py
+++ b/server/szurubooru/tests/api/test_tag_updating.py
@@ -136,6 +136,7 @@ def test_trying_to_create_tags_without_privileges(
                     params={'suggestions': ['tag1', 'tag2'], 'version': 1},
                     user=user_factory(rank=db.User.RANK_REGULAR)),
                 {'tag_name': 'tag'})
+        db.session.rollback()
         with pytest.raises(errors.AuthError):
             api.tag_api.update_tag(
                 context_factory(