In The Unicode Standard, Limbu script implementation is discussed in  Chapter 13 South and Central Asia-II: Other Modern Scripts.

The Limbu script was encoded in The Unicode Standard version 4.0. The script is encoded in the following block:

BlocksCharacter RangeAdded in Unicode VersionUnicode Chart
Limbu 1900..194F 4.0  U1900.pdf

Subsequent to version 4.0, the following characters have been added to the script:

CharactersUnicode VersionDocumentation
191D..191E 7.0  WG2 N3975/ L2/11-008

Documentation refers to  ISO Working Group and Unicode proposals

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

1992-10-30 Kirat (Limbu) — Rick McGowan ( Unicode Technical Report #3 R2)

1999-07-20 Unicode Technical Report #3: Early Aramaic, Balti, Kirat (Limbu), Manipuri (Meitei), and Tai Lü scripts — Rick McGowan, Michael Everson ( WG2 N2042,  L2/99-245)

2001-03-29 Draft proposal: Unicode coding of the Limbu Script — Boyd Michailovsky ( L2/01-137)

2001-03-29 Proposal summary form for the Limbu Script — Boyd Michailovsky ( L2/01-138)

2001-03-29 Printed samples of the Limbu Script — Boyd Michailovsky ( L2/01-139)

2001-03-29 Proposal to encode Limbu in the BMP — Boyd Michailovsky ( WG2 N2339,  L2/01-231)

2002-02-05 Revised proposal to encode the Limbu script in the UCS — Boyd Michailovsky, Michael Everson ( WG2 N2410,  L2/02-055)

2002-03-25 Comments from Limbu experts on n2339 — Takayuki K. Sato ( WG2 N2428-1.doc,  L2/02-135)

2002-04-09 Limbu Examples — Kumar Limbu ( WG2 N2428-3,  L2/02-137)

2002-04-09 Comments on the “Proposal to encode Limbu in the UCS” — Til Bikram Nembang, Dr. Madhav Prasad Pokharel, Dilendra Kurumbang, Kumar Limbu ( WG2 N2428-2,  L2/02-136)

2003-08-13 Introduction to the Limbu Script — Daniel Kai ( L2/03-255)

2003-08-13 Lepcha, Limbu, Syloti, Saurashtra, Tai Le and Bugis Proposals — Daniel Kai ( L2/03-253)

2004-03-09 Indic scripts collation grouping; CTT suggestion — Kent Karlsson ( WG2 2716.doc,  L2/04-109)

2005-02-07 Issues in Representation of Indic Scripts in Unicode (Unicode Conference Presentation) — Om Vikas ( L2/05-063)

2005-10-21 General category and bidi property for some Indic characters — Asmus Freytag ( L2/05-304)

2005-10-24 Comments on 5.0 properties, and property consistency, for some Indic characters (introduced before 5.0) — Kent Karlsson ( L2/05-316)

2011-01-14 Proposal to Encode the Letters GYAN and TRA for Limbu in the UCS — Anshuman Pandey ( WG2 N3975,  L2/11-008 )

2014-02-05 A bag of suggested improvements to Unicode’s provisional Indic properties — Roozbeh Pournader, Behdad Esfahbod ( L2/14-065)

2014-05-08 Improvements requested for Unicode Indic properties — Roozbeh Pournader ( L2/14-126)