FamilySearch Releases GEDCOM Version 5.5.1      
GEDCOM is an abbreviation that stands for 
GEnealogy 
Data 
COMmunications. In short, GEDCOM is the language by which different genealogy software programs talk to one another.
GEDCOM was developed by the Family History Department of The Church 
of Jesus Christ of Latterday Saints (LDS Church) to provide a flexible, 
uniform format for exchanging computerized genealogical data.
GEDCOM is not a program. Instead, it is a specification of the method
 that different genealogy programs should use to exchange data. The 
purpose is to exchange data between dissimilar programs without having 
to manually re-enter all the data on a keyboard. A GEDCOM file is a 
plain text file (usually either UTF-8, ANSEL or ASCII) containing 
genealogical information about individuals, and meta data linking these 
records together.
All of today’s more popular genealogy programs will import and export
 GEDCOM data. However, the GEDCOM standard first adopted in 1985 did not
 envision today’s environment of multimedia files, such as digital 
pictures, video, audio, text files using non-English alphabets 
(Cyrillic, Bulgarian, Hindi, Chinese, Japanese, Hebrew, and other 
languages), links to external data stored in the World Wide Web, and 
many more commonly-used standards of today.
Over the years, the GEDCOM standard has been updated several times 
with each update adding new functionality and significantly improving 
the standard. However, because of the constantly evolving improvements 
in genealogy programs, data transferred via GEDCOM often has not been 
perfect. After transferring from one program to another, manual 
“clean-up” has often been required to fix any data that was not 
transferred properly.
Now FamilySearch has released a new update: GEDCOM 5.5.1
This is the first update in ten years. The new GEDCOM 5.5.1 standard may be found at: 
https://edge.fscdn.org/assets/img/documents/ged551-5bac5e57fe88dd37df0e153d9c515335.pdf. The most important part of that document is listed in the section entitled 
Modifications in Version 5.5.1 that starts on page 6 of that document.
While there are numerous changes and clarifications, perhaps the most interesting items are the new tags added in GEDCOM 5.5.1:
EMAIL electronic mailing address
FAX FAX address
FACT A fact or characteristic.
FONE Phonetic variation of a text.
ROMN Romanized variation of a text.
WWW Web Home page address.
MAP Pertaining to maps.
LATI value of a latitudinal coordinate pertaining to the place of an event
LONG value of a longitudinal coordinate pertaining to the place of an event.
What will the impact of GEDCOM 5.5.1 mean to non-programmers?
Nothing will change immediately for most users. However, the new 
update does mean that the programmers who write the many genealogy 
programs will need to update their products and then release new 
updates. As these updated products become available, anyone using a 
newly-updated genealogy product that conforms to GEDCOM 5.5.1 can 
exchange data with more accuracy with anyone else who is also using a 
GEDCOM 5.5.1-compatible genealogy program.
 
Informations from FamilySearch (by asking about 5.5.5):
“The Church of Jesus Christ has the copyright on the Gedcom Specification since 1987. There has not been a legal transfer of the rights we have to the Gedcom Specification.”
So 5.5.5 is not a legal GEDCOM version.