diff --git a/filer/__init__.py b/filer/__init__.py
index 548842206..ebb66f92f 100644
--- a/filer/__init__.py
+++ b/filer/__init__.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
 # version string following pep-0440
-__version__ = '0.9.112'  # pragma: nocover
+__version__ = '0.9.116'  # pragma: nocover
 
 default_app_config = 'filer.apps.FilerConfig'
diff --git a/filer/management/commands/fixfoldertrees.py b/filer/management/commands/fixfoldertrees.py
index 45f4976ab..fa164a954 100644
--- a/filer/management/commands/fixfoldertrees.py
+++ b/filer/management/commands/fixfoldertrees.py
@@ -14,6 +14,11 @@ def add_arguments(self, parser):
                             default=False,
                             help='Performs only a check for corrupted folder trees. '
                                  'Prints all the corruptions it finds.')
+        parser.add_argument('--force-rebuild',
+                            action='store_true',
+                            dest='force_full_rebuild',
+                            default=False,
+                            help='Force a full tree rebuild.')
 
     def handle(self, *args, **options):
         checker = TreeChecker()
@@ -39,4 +44,20 @@ def handle(self, *args, **options):
             else:
                 self.stdout.write("There are no corruptions\n")
         else:
-            checker.rebuild()
+            if options['force_full_rebuild']:
+                self.stdout.write("\nPerforming full rebuild...")
+                checker.manager.rebuild()
+            else:
+                self.stdout.write("Checking folder trees before fixing...\n")
+                checker.check_corruptions()
+                if checker.full_rebuild:
+                    self.stdout.write("\nPerforming full rebuild...")
+                    checker.manager.rebuild()
+                elif checker.corrupted_folders:
+                    self.stdout.write("\nPerforming corrupted folders rebuild...")
+                    for folder in checker.get_corrupted_root_nodes():
+                        self.stdout.write(f"\n\tPerforming partial rebuild for folder {folder.name}")
+                        checker.manager.partial_rebuild(folder.tree_id)
+                else:
+                    self.stdout.write("There are no corruptions, nothing to be done.\n")
+            self.stdout.write("\nRebuild Done.")
diff --git a/filer/migrations/0006_default_caption_text_size.py b/filer/migrations/0006_default_caption_text_size.py
new file mode 100644
index 000000000..32f60395c
--- /dev/null
+++ b/filer/migrations/0006_default_caption_text_size.py
@@ -0,0 +1,15 @@
+from django.db import migrations, models
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('filer', '0005_default_alt_text_size'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='Image',
+            name='default_caption',
+            field=models.TextField(null=True), # Use TextField to allow unlimited length
+        ),
+    ]
\ No newline at end of file
diff --git a/filer/models/imagemodels.py b/filer/models/imagemodels.py
index c6d39f6a9..66c3ac052 100644
--- a/filer/models/imagemodels.py
+++ b/filer/models/imagemodels.py
@@ -9,7 +9,6 @@
     except ImportError:
         raise ImportError("The Python Imaging Library was not found.")
 from datetime import datetime
-from django.urls import reverse
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 from django.utils import timezone
@@ -17,7 +16,6 @@
 from django.core.exceptions import ValidationError
 from filer import settings as filer_settings
 from filer.models.filemodels import File
-from filer.utils.filer_easy_thumbnails import FilerThumbnailer
 from filer.utils.pil_exif import get_exif_for_file
 import os
 
@@ -36,7 +34,7 @@ class Image(File):
     }
     file_type = 'Image'
     _icon = "image"
-    _filename_extensions = ['.jpg', '.jpeg', '.png', '.gif', '.ico']
+    _filename_extensions = ['.jpg', '.jpeg', '.png', '.gif', '.ico', '.svg', '.webp']
 
     _height = models.IntegerField(null=True, blank=True)
     _width = models.IntegerField(null=True, blank=True)
@@ -44,17 +42,17 @@ class Image(File):
     date_taken = models.DateTimeField(_('date taken'), null=True, blank=True,
                                       editable=False)
 
-    default_alt_text = models.CharField(
-        _('default alt text'), max_length=255, blank=True, null=True,
+    default_alt_text = models.TextField(
+        _('default alt text'), blank=True, null=True,
         help_text=_('Describes the essence of the image for users who have '
                     'images turned off in their browser, or are visually '
                     'impaired and using a screen reader; and it is used to '
                     'identify images to search engines.'))
-    default_caption = models.CharField(
-        _('default caption'), max_length=255, blank=True, null=True,
+    default_caption = models.TextField(
+        _('default caption'), blank=True, null=True,
         help_text=_('Caption text is displayed directly below an image '
-                    'plugin to add context; there is a 140-character limit,'
-                    ' including spaces; for images fewer than 200 pixels '
+                    'plugin to add context; there is no character limit;'
+                    'for images fewer than 200 pixels '
                     'wide, the caption text is only displayed on hover.'))
     default_credit = models.CharField(
         _('default credit text'), max_length=255, blank=True, null=True,
@@ -95,10 +93,6 @@ def clean(self):
             raise ValidationError(
                 "Ensure default credit text has at most 30 characters ("
                 "%s characters found)." % len(self.default_credit))
-        if int(len(self.default_caption or '')) > 140:
-            raise ValidationError(
-                "Ensure default caption text has at most 140 characters ("
-                "%s characters found)." % len(self.default_caption))
         super(Image, self).clean()
 
     def save(self, *args, **kwargs):
diff --git a/filer/utils/checktrees.py b/filer/utils/checktrees.py
index 836cae099..1a0b4ee0e 100644
--- a/filer/utils/checktrees.py
+++ b/filer/utils/checktrees.py
@@ -6,7 +6,6 @@ class TreeCorruption(Exception):
 
 
 class TreeChecker(object):
-
     ordering = ['tree_id', 'lft', 'rght']
 
     def __init__(self, folder_manager=None):
@@ -19,14 +18,13 @@ def __init__(self, folder_manager=None):
         else:
             self.manager = folder_manager
 
-
     def find_corruptions(self):
         self.check_corruptions()
         if (self.full_rebuild or self.corrupted_folders):
             raise TreeCorruption()
 
     def _build_diff_msg(self, expected, actual):
-        attr_idx = {'lft':0, 'rght':1, 'level':2, 'tree_id':3}
+        attr_idx = {'lft': 0, 'rght': 1, 'level': 2, 'tree_id': 3}
         expected, actual = list(expected), list(actual)
         diff = []
         for attr, idx in list(attr_idx.items()):
@@ -50,29 +48,31 @@ def get_corrupted_root_nodes(self):
         if not self.corruption_check_done:
             self.check_corruptions()
         corrupted_trees = self.manager.filter(
-            pk__in=list(self.corrupted_folders.keys())).\
+            pk__in=list(self.corrupted_folders.keys())). \
             values_list('tree_id', flat=True).distinct()
         return self.manager.filter(
-            parent__isnull=True, tree_id__in=corrupted_trees)
+            parent__isnull=True, deleted_at__isnull=True, tree_id__in=corrupted_trees)
 
     def check_tree(self, pk, lft, tree_id, level=0):
         """
             * checks if a certain folder tree is corrupted or not.
             * uses the same logic as django-mptt's rebuild tree
+            * ignores deleted folders, same as django-mptt's rebuild
         """
         rght = lft + 1
-        child_ids = self.manager.filter(parent__pk=pk).\
+        child_ids = self.manager.filter(parent__pk=pk). \
             order_by(*self.ordering).values_list('pk', flat=True)
 
         for child_id in child_ids:
             rght = self.check_tree(child_id, rght, tree_id, level + 1)
 
         folder = self.manager.get(pk=pk)
-        expected = (lft, rght, level, tree_id)
-        actual = (folder.lft, folder.rght, folder.level, folder.tree_id)
-        if expected != actual:
-            self.corrupted_folders.setdefault(
-                pk, self._build_diff_msg(expected, actual))
+        if folder.deleted_at is None:
+            expected = (lft, rght, level, tree_id)
+            actual = (folder.lft, folder.rght, folder.level, folder.tree_id)
+            if expected != actual:
+                self.corrupted_folders.setdefault(
+                    pk, self._build_diff_msg(expected, actual))
         return rght + 1
 
     def check_corruptions(self):
@@ -82,15 +82,15 @@ def check_corruptions(self):
             * checks if there are multiple root folders with the
         same tree id(fixing this will require a full rebuild)
         """
-        tree_duplicates = self.manager.filter(parent=None).\
-            values_list('tree_id').\
+        tree_duplicates = self.manager.filter(parent=None). \
+            values_list('tree_id'). \
             annotate(count=Count('id')).filter(count__gt=1)
         if len(tree_duplicates) > 0:
             self.full_rebuild = True
             self.corruption_check_done = True
             return
 
-        pks = self.manager.filter(parent=None).\
+        pks = self.manager.filter(parent=None). \
             order_by(*self.ordering).values_list('pk', flat=True)
         idx = 0
         for pk in pks:
@@ -107,7 +107,4 @@ def rebuild(self):
             self.manager.rebuild()
         elif self.corrupted_folders:
             for folder in self.get_corrupted_root_nodes():
-                # since we use an older version of djang-mptt and method
-                #   partial_rebuild does not exist ...
-                self.manager._rebuild_helper(
-                    folder.pk, 1, folder.tree_id)
+                self.manager.partial_rebuild(folder.tree_id)
diff --git a/setup.py b/setup.py
index 6b218a198..c26d0f6ed 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,7 @@
-from setuptools import setup, find_packages
 import os
 
+from setuptools import setup, find_packages
+
 try:
     from setuptest import test
 except ImportError:
@@ -25,8 +26,9 @@ def read(fname):
     author_email='stefan.foulis@gmail.com',
     packages=find_packages(),
     install_requires=(
+        'django-js-asset==2.0.0',
         'django>=1.11,<3.0',
-        'django-mptt>=0.6,<1.0',  # the exact version depends on Django
+        'django-mptt==0.11.1',  # the exact version depends on Django
         'django_polymorphic>=0.7,<2.2',
         'easy-thumbnails>=2,<3.0',
         'Unidecode>=0.04,<1.2',