Overview
TMG to GEDCOM writes GEDCOM files following either the GEDCOM 5.5.1 specification or the GEDCOM 7.0 specification.
GEDCOM 5.5.1
GEDCOM 5.5.1 was published in draft form by the Family History Department of The Church of Jesus Christ of Latter-day Saints in 1999. Despite its draft status, many products adopted GEDCOM 5.5.1 because it was superior to prior versions and included some very important changes, such as support for the UTF-8 character encoding.
The Family History Department published GEDCOM 5.5.1 in November 2019 where the only change was to remove its draft status.
When it was originally released in 1999, GEDCOM 5.5.1 was already out-of-date with respect to commonly accepted technological practices, and that problem grew worse with each passing year. In response, software authors and publishers introduced proprietary solutions. Combined with ambiguities in the specification and failure to understand the specification, data transfer using GEDCOM 5.5.1 is a significant challenge. TMG to GEDCOM has dozens of properties and uses Templates to provide the appropriate values for those properties in an attempt to write GEDCOM files that (mostly) follow the GEDCOM 5.5.1 specification but are customized to the requirements of the target software.
GEDCOM 7.0
GEDCOM 7.0 was originally published in 2021. The Family History Department has published several "patch" versions since then. According to the specification, "A new patch version is a clarified or improved specification for the same data and introduces no changes in the data itself."
As of 2024, GEDCOM 7 has not been widely adopted. That will change as new and updated versions of genealogical programs are released.
The GEDCOM 7 specification includes a brief summary of its purpose. The end result is GEDCOM 7.0 solves many of the issues in GEDCOM 5.5.1. Still, no specification is perfect, and the specification continues to evolve as indicated by the release of "patch" versions.
Property Reduction
Due to the resolution of ambiguities in GEDCOM 5.5.1, and the effort to make the GEDCOM 7 specification align with current technological standards and practices, there are fewer valid alternatives for converting TMG data into GEDCOM 7 records as compared to converting TMG data into GEDCOM 5.5.1 records. As a result, when the GEDCOM Format.Gedcom Version property is set to "7.0", TMG to GEDCOM disables and/or ignores many other properties.
Example
The Event structure in GEDCOM 5.5.1 did not include a TAG to supply a sort date. To get around that limitation, some programs used a custom _SDATE TAG to specify a sort date. There was no guarantee that the target program would import the sort date value and no guarantee that _SDATE was the proper GEDCOM TAG to use for it.
For GEDCOM 5.5.1, TMG to GEDCOM includes the GEDCOM Tags.Sort Date Tag property to indicate which TAG to use and includes the Dates.Include Sort Dates property to indicate whether to write sort date TAGs.
GEDCOM 7.0 includes support for sort dates via the SDATE TAG. When the GEDCOM Format.Gedcom Version property is set to "7.0", TMG to GEDCOM ignores the GEDCOM Tags.Sort Date Tag and Dates.Include Sort Dates properties.