diff --git a/cloudkitty/utils.py b/cloudkitty/utils.py
index 4b865284..3ab25b68 100644
--- a/cloudkitty/utils.py
+++ b/cloudkitty/utils.py
@@ -106,6 +106,27 @@ def isotime(at=None, subsecond=False):
     return st
 
 
+def iso8601_from_timestamp(timestamp, microsecond=False):
+    """Returns an iso8601 formatted date from timestamp"""
+
+    # Python provides a similar instance method for datetime.datetime
+    # objects called isoformat() and utcfromtimestamp(). The format
+    # of the strings generated by isoformat() and utcfromtimestamp()
+    # have a couple of problems:
+    # 1) The method iso8601_from_timestamp in oslo_utils is realized
+    #    by isotime, the strings generated by isotime are used in
+    #    tokens and other public APIs that we can't change without a
+    #    deprecation period. The strings generated by isoformat are
+    #    not the same format, so we can't just change to it.
+    # 2) The strings generated by isoformat() and utcfromtimestamp()
+    #    do not include the microseconds if the value happens to be 0.
+    #    This will likely show up as random failures as parsers may be
+    #    written to always expect microseconds, and it will parse
+    #    correctly most of the time.
+
+    return isotime(datetime.datetime.utcfromtimestamp(timestamp), microsecond)
+
+
 def dt2ts(orig_dt):
     """Translate a datetime into a timestamp."""
     return calendar.timegm(orig_dt.timetuple())
@@ -129,7 +150,7 @@ def ts2iso(timestamp):
     """timestamp to is8601 format."""
     if not isinstance(timestamp, float):
         timestamp = float(timestamp)
-    return timeutils.iso8601_from_timestamp(timestamp)
+    return iso8601_from_timestamp(timestamp)
 
 
 def dt2iso(orig_dt):