## Changes Introduced in V5.5-0

The following describes the most significant changes which occurred in the AST library between versions V5.4-0 and V5.5-0:

1. The FitsChanFitsChan “TabOKTabOK” attribute is now an integer value rather than a boolean value. If TabOK is set to a non-zero positive integer before invoking the astWriteastWrite method, its value is used as the version number for any table that is created as a consequence of the write operation. This is the value stored in the PVi_1a keyword in the IMAGE header, and the EXTVER keyword in the binary table header. In previous versions of AST, the value used for these headers could not be controlled and was fixed at 1. If TabOK is set to a negative or zero value, the -TAB algorithm will not be supported by either the astWrite or astReadastRead methods.