ECN-4481 Vision 2 file format support discontinued

Support for the Vision 2 file format is discontinued in this version of the extend Interoperability Suite. The Vision 2 file format was not portable between systems with different architectures, and was superseded by the Vision 3 file format over 24 years ago. Use of the Vision 2 file format has not been recommended for a very long time.

Any remaining Vision 2 files should be rebuilt to a newer Vision file format; see Rebuilding Files for more details. Vision 3 is a portable single-file format containing the index and records in a single file, and is limited to file sizes less than 2GB; Vision 4 and Vision 5 are portable dual file formats using multiple segments to support large files; and Vision 6 is a portable dual file format supporting files larger than 2GB. Vision 6 is the default Vision file format, and for best results use this file format where possible.