Error updating fdroid repository

When I execute fdroid update, I obtain the next error

WARNING: repo/otr.apk is debuggable... densities: '120' '160' '240' '320'
Traceback (most recent call last):
  File "/usr/bin/fdroid", line 66, in <module>
    main()
  File "/usr/bin/fdroid", line 62, in main
    mod.main()
  File "/usr/lib/python2.7/dist-packages/fdroidserver/update.py", line 935, in main
    apks, cc = scan_apks(apps, apkcache, repodirs[0], knownapks)
  File "/usr/lib/python2.7/dist-packages/fdroidserver/update.py", line 463, in scan_apks
    apk = zipfile.ZipFile(apkfile, 'r')
  File "/usr/lib/python2.7/zipfile.py", line 770, in __init__
    self._RealGetContents()
  File "/usr/lib/python2.7/zipfile.py", line 857, in _RealGetContents
    x._decodeExtra()
  File "/usr/lib/python2.7/zipfile.py", line 388, in _decodeExtra
    tp, ln = unpack('<HH', extra[:4])
struct.error: unpack requires a string argument of length 4