Version 1.5
~~~~~~~~~~~
Version for DiFX-2.5, May 16, 2017
* Added crossed auto correlations to type 1 files

Version 1.4
~~~~~~~~~~~
Version for DiFX-2.4, Nov 4, 2014
* support mixed/zoom mode correlations
* support version 1 file format for pcal
* in mixed mode denote sidebands as upper for hops

Version 1.3
~~~~~~~~~~~
Version for DiFX-2.3, Dec 20, 2013
* put data weights into type 120 record

Version 1.2
~~~~~~~~~~~
Version for DiFX-2.2, June 1, 2013

Version 1.1
~~~~~~~~~~~
Post DiFX 2.0.1
Version for DiFX-2.1, May 4, 2012

Version 1.0
~~~~~~~~~~~
For DiFX 2.0.1, tagged June 12, 2011