In The Unicode Standard, Soyombo script implementation is discussed in  Chapter 14 South and Central Asia-III: Ancient Scripts.

The Soyombo script was first encoded in The Unicode Standard version 10.0. The script is encoded in the following block:

BlocksCharacter RangeAdded in Unicode VersionDocumentation
Soyombo 11A50..11AAF 10.0  U11A50

A number of proposals for its inclusion have been submitted to the Unicode Technical Committee and WG2:

1998-08-21 Addition of Soyombo script to ISO 10646 — Mongol & Japan ( WG2 N1855,  L2/98-358)

2000-01-06 Soyombo and Pagba (old Mongol scripts) — Takayuki K. Sato ( WG2 N2163,  L2/00-055)

2010-10-30 Preliminary Proposal to Encode the Soyombo Script in ISO/IEC 10646 — Anshuman Pandey ( WG2 N3949,  L2/10-399)

2010-11-11 Comments on Soyombo and Xawtaa Dorboljin — Shriramana Sharma ( L2/10-467)

2011-02-05 Determining the Encoding Model for Soyombo Vowels — Anshuman Pandey ( WG2 N3986,  L2/11-054)

2011-04-25 Revised Preliminary Proposal to Encode Soyombo in the UCS — Anshuman Pandey ( WG2 N4026,  L2/11-125)

2011-10-25 Proposal to Encode the Soyombo Script in ISO/IEC 10646 — Anshuman Pandey ( WG2 N4142,  L2/11-412)

2013-04-22 Revised Proposal to Encode the Soyombo Script in ISO/IEC 10646 — Anshuman Pandey ( WG2 N4414,  L2/13-069)

2013-04-25 Comments on the proposed Soyombo encoding — Shriramana Sharma ( L2/13-075)

2015-01-26 Proposal to Encode the Soyombo Script in ISO/IEC 10646 — Anshuman Pandey (WG2 N4655,  L2/15-004)

2015-01-26 Comments on Proposals of Zanabazar Square and Soyombo Script from Mongolian Experts — Toshiya Suzuki, Takashi Matsukawa, Hitoshi Kuribayashi (WG2 N4653,  L2/15-009)

2015-02-09 Response to Mongolian and Japanese comments on Soyombo and Zanabazar Square — Anshuman Pandey ( L2/15-094)

2015-10-17 Summary of Ad Hoc Meeting on Two Historical Scripts from Mongolia (Tokyo, Japan) — Deborah Anderson ( L2/15-249)

2015-10-20 The Comments on Square script & Soyombo encoding project — R.Otgonbaatar ( L2/15-248)

2015-10-20 Revised code chart and names list for Soyombo — Anshuman Pandey ( L2/15-247)

2015-12-03 Proposal to encode JIHVAMULIYA and UPADHMANIYA for Soyombo — Anshuman Pandey ( L2/15-331)

UTC #146 Minutes ( L2/16-004) (See D.10.3 for decision and action items)

2015-12-07 Comments on L2/15-249 regarding Soyombo and Zanabazar Square punctuation — SEI / Anshuman Pandey ( L2/15-336)

UTC #146 Minutes ( L2/16-004) (See D.10.2 for decision and action items)

2016-01-06 Proposal to encode the Soyombo mark PLUTA — Anshuman Pandey ( L2/16-016)

UTC #146 Minutes ( L2/16-004) (See D.10.1 for decision and action items)

2017-07-21 Proposal to encode JIHVAMULIYA and UPADHMANIYA for Soyombo — Anshuman Pandey ( L2/17-235)

Recommendations to UTC #152 July-August 2017 on Script Proposals ( L2/17-255) (See point 18.)

UTC #152 Minutes ( L2/17-222) (See D.5 for decision and action items)