Use str just in case.

avatar/models.py

@@ -7,10 +7,14 @@ from django.db import models
 from django.core.files.base import ContentFile
 from django.core.files.storage import get_storage_class
 from django.utils.translation import ugettext as _
-from django.utils.encoding import force_bytes
 from django.utils import six
 from django.db.models import signals
 
+try:
+    from django.utils.encoding import force_bytes
+except ImportError:
+    force_bytes = str
+
 from avatar.util import get_username
 
 try:

avatar/templatetags/avatar_tags.py

@@ -10,9 +10,13 @@ from django import template
 from django.core.urlresolvers import reverse
 from django.template.loader import render_to_string
 from django.utils import six
-from django.utils.encoding import force_bytes
 from django.utils.translation import ugettext as _
 
+try:
+    from django.utils.encoding import force_bytes
+except ImportError:
+    force_bytes = str
+
 from avatar.settings import (AVATAR_GRAVATAR_BACKUP, AVATAR_GRAVATAR_DEFAULT,
                              AVATAR_DEFAULT_SIZE, AVATAR_GRAVATAR_BASE_URL)
 from avatar.util import (get_primary_avatar, get_default_avatar_url,

avatar/util.py

@@ -2,10 +2,14 @@ import hashlib
 
 from django.conf import settings
 from django.core.cache import cache
-from django.utils.encoding import force_bytes
 from django.utils import six
 from django.template.defaultfilters import slugify
 
+try:
+    from django.utils.encoding import force_bytes
+except ImportError:
+    force_bytes = str
+
 try:
     from django.contrib.auth import get_user_model
 except ImportError: