Error after upgrading from version 5.8 to version 5.11

I just upgraded from version 5.8 to version 5.11. When I run getmail it
produces the following error message:


  getmail version 5.11
  Python version 2.6.6 (r266:84292, Aug 18 2016, 15:13:37) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)]

Unhandled exception follows:
    File "/usr/bin/getmail", line 898, in main
    success = go(configs, options.idle)
    File "/usr/bin/getmail", line 157, in go
    retriever.initialize(options)
    File "/usr/lib/python2.6/site-packages/getmailcore/_retrieverbases.py",
line 1723, in initialize
    self._connect()
    File "/usr/lib/python2.6/site-packages/getmailcore/_retrieverbases.py",
line 657, in _connect
    self.conf['port'])
    File "/usr/lib64/python2.6/imaplib.py", line 1150, in __init__
    IMAP4.__init__(self, host, port)
    File "/usr/lib64/python2.6/imaplib.py", line 172, in __init__
    self.open(host, port)
    File "/usr/lib64/python2.6/imaplib.py", line 1162, in open
    self.sslobj = ssl.wrap_socket(self.sock, self.keyfile, self.certfile)
    File "/usr/lib/python2.6/site-packages/getmailcore/_retrieverbases.py",
line 101, in _wrap_socket
    ciphers=ciphers)
  TypeError: __init__() got an unexpected keyword argument 'ciphers'


I am running getmail on CentOS 6.9.

Any suggestions?