In The Unicode Standard, Devanagari script implementation is discussed in  Chapter 12 South and Central Asia-I: Official Scripts of India.

The Devanagari script was first encoded in The Unicode Standard version 1.0. The script is now encoded in the following blocks:

BlocksCharacter RangeAdded in Unicode VersionUnicode Charts
Devanagari 0900..097F 1.0  U0900
Devanagari Extended A8E0..A8FF 5.2  UA8E0

Vedic Extensions may be used with the Devanagari script as well as many other Indic scripts.

Subsequent to version 1.0, the following characters have been added to the Devanagari script:

CharactersUnicode VersionDocumentation
0900 5.2  n3235.pdf/ L2/07-095,  n3383.pdf/ L2/08-050,  n3385.pdf/ L2/08-092 (comparison between n3235 and n3383)
0904 4.0  n2425.pdf/ L2/02-117
093A..093B 6.0  n3731.pdf/ L2/09-389
094E 5.2  n3235.pdf/ L2/07-095,  n3383.pdf/ L2/08-050,  n3385.pdf/ L2/08-092 (comparison between n3235 and n3383)
094F 6.0  n3731.pdf/ L2/09-389
0955 5.2  n3235.pdf/ L2/07-095,  n3383.pdf/ L2/08-050,  n3385.pdf/ L2/08-092 (comparison between n3235 and n3383)
0956..0957 6.0  n3731.pdf/ L2/09-389
0971 5.1  n3125.pdf/ L2/06-137
0972 5.1  n3249.pdf/ L2/07-027R
0973..0977 6.0  n3731.pdf/ L2/09-389
0978 7.0  WG2 N3970,  L2/10-475
0979..097A 5.2  n3235.pdf/ L2/07-095,  n3383.pdf/ L2/08-050,  n3385.pdf/ L2/08-092 (comparison between n3235 and n3383)
097B..097C 5.0  n2934.pdf/ L2/05-082
097D 4.1  n2543.pdf/ L2/02-394
097E..097F 5.0  n2934.pdf/ L2/05-082
A8E0..A8FB 5.2  n3235.pdf/ L2/07-095,  n3383.pdf/ L2/08-050,  n3385.pdf/ L2/08-092 (comparison between n3235 and n3383)
A8FC 8.0  WG2 N4260,  L2/12-123
A8FD 8.0  WG2 N4408,  L2/13-056
A8FE..A8FF pending  L2/15-335

Documentation refers to  ISO Working Group and Unicode proposals

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

1998-05-25 Nepali Font Standards - White Paper Version 2 — Nepali Font SC ( L2/99-235)

1999-01-27 3.0 Devanagari--Eyelash RA (third version) — James E. Agenbroad ( L2/99-026)

1999-02-04 Specification of UTC Resolution on Eyelash RA — Joe Becker ( L2/99-046)

1999-03-05 Proposal for encoding Nepalese script in the ISO/IEC 10646 — CSNC Nepal ( WG2 N1999.doc,  L2/99-234)

1999-07-29 Comment on Proposal for Nepalese Script — Hugh McG Ross ( WG2 N2055) —

2000-11-14 Why does Unicode need revision for Indic scripts? — S.P. Mudur, India ( L2/00-406)

2000-11-15 Unicode representation of Indian Scripts — M.N. Cooper ( L2/00-417)

2002-01-14 Character Properties for avagrahas, etc. — Kenneth Whistler ( L2/02-017)

2002-03-21 Additional Characters for Indic Scripts — Rick McGowan ( WG2 N2425,  L2/02-117)

2002-05-15 Status in Nepal on n2055 (UK comment on encoding request for Nepali n1999-Nepal) — Takayuki K. Sato ( WG2 N2466.doc,  L2/02-215)

2002-11-01 Proposal for Encoding Devanagari Glottal Stop — Peter Constable, Steve Smith ( WG2 N2543,  L2/02-394)

2002-12-20 Comments on some proposals for revision of Devanagari Encoding in Unicode — Peri Bhaskararao ( L2/02-402)

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

2004-05-18 Encoding of Devanagari Rupee Sign in Devanagari code block — Gov't of India ( L2/04-236)

2004-06-30 Proposal on Clarification and Consolidation of the Function of ZERO WIDTH JOINER in Indic Scripts — Peter Constable ( L2/04-279)

2004-08-04 Response to Public Review Issue #37 — Antoine Leca ( L2/04-328)

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

2005-03-30 Proposal to add four characters for Sindhi to the BMP of the UCS — Michael Everson ( WG2 N2934,  L2/05-082)

2005-05-11 Comments on PRI 65: Devanagari Eyelash Ra — Eric Muller ( L2/05-147)

2006-04-20 Proposal to encode Devanagari Sign High Spacing Dot — Jonathan Kew, Steve Smith ( L2/06-137)

2006-05-14 Latin Dandas — Stefan Baums ( L2/06-203)

2006-06-17 Comments on Indic Block Descriptions — Peter Constable ( L2/06-225)

2006-07-03 Proposal to add four characters for Kashmiri to the BMP of the UCS — Michael Everson, Pravin Satpute ( WG2 N3480,  L2/08-250)

2006-11-04 Proposal for additional character (in Devanagari) — Gov't of India ( L2/06-373)

2006-11-07 Comments on L2/06-373 (addition of 'apostrophe' to Devanagari) — Anshuman Pandey ( L2/06-398)

2007-01-24 Encoded Representation of Devanagari Candra A — Peter Constable ( L2/07-027)

2007-04-13 Proposal to encode characters for Vedic Sanskrit in the BMP of the UCS — Michael Everson and Peter Scharf (editors), Michel Angot, R. Chandrashekar, MalcolmHyman, Susan Rosenfield, B. V. Venkatakrishna Sastry, Michael Witzel ( WG2 N3235,  L2/07-095)

2007-04-20 Proposal to Encode Devanagari Letter Candra A in the UCS L2 / Constable ( L2/07-133)

2007-05-15 Proposal to Encode North Indian Accounting Signs in Plane 1 of ISO/IEC 10646 — Anshuman Pandey ( WG2 N3312,  L2/07-139)

2007-07-31 Towards an Encoding for North Indic Number Forms in the UCS — Anshuman Pandey ( WG2 N3334,  L2/07-238)

2007-10-07 Proposal to Encode North Indic Number Forms in ISO/IEC 10646 — Anshuman Pandey ( WG2 N3367,  L2/07-354)

2007-10-14 Changes in L2/07-354 North Indic Number Forms (vs. L2/07-139) — Deborah Anderson ( L2/07-390)

2008-01-31 Comparison between two Vedic proposals of January 2008 — Michael Everson, Peter Scharf ( WG2 N3385,  L2/08-092)

2008-03-02 Criteria for the encoding of script-specific dandas — Unicode and US National Body ( WG2 N3457,  L2/08-118)

2008-03-06 Summary proposal to encode characters for Vedic in the BMP of the UCS — Michael Everson ( WG2 N3383,  L2/08-050)

2008-05-06 Representation of Bodo, Dogri and Maithili languages in Unicode Standard — Gov't of India ( L2/08-197)

2008-05-07 Usage examples for Bodo, Dogri, Maithili tone marker — Swaran Lata ( L2/08-210)

2008-08-06 Placement of characters in Vedic, Devanagari, and Devanagari Extended blocks — Peter Scharf ( L2/08-294)

2008-08-08 Materials for a Proposal to encode the Devanagari headstroke in the BMP of the Unicode Standard — Peter Scharf ( L2/08-295)

2009-01-07 Encoding of additional characters in Unicode for representation of Kashmiri — Swaran Lata ( L2/09-012)

2009-08-11 Encoding of additional characters in Unicode for representation of Kashmiri — Swaran Lata ( L2/09-311)

2009-09-18 Proposal to Encode Additional Short Vowel Characters for Devanagari — Anshuman Pandey ( L2/09-320)

2009-09-22 Proposal to Deprecate Devanagari Short Letter A — Anshuman Pandey ( L2/09-321)

2009-10-06 Request for normative aliases for some generic Indic characters — Shriramana Sharma ( L2/09-339)

2009-10-09 Request for change of annotation of 0951 Devanagari Stress Sign Udatta — Shriramana Sharma ( L2/09-340)

2009-10-14 Proposal to add Six characters in the Devanagari block for representation of Kashmiri language in Devanagari script — India NB ( WG2 N3710,  L2/09-369)

2009-10-26 Comments on India’s Proposal to Add Devanagari Characters for Kashmiri (N3710 L2/09-369) — Anshuman Pandey ( L2/09-377)

2009-10-28 Consensus on Kashmiri additions for Devanagari — Michael Everson ( WG2 N3731,  L2/09-389)

2009-10-30 Comments on 'Consensus on Kashmiri additions for Devanagari' (N3727 L2/09-389) — Anshuman Pandey ( L2/09-403)

2010-01-25 Additions to Deva-Nagari Script & Bengali Script — Rabin Deka ( L2/10-029)

2010-01-27 Comments on Additions to Deva-Nagari Script & Bengali Script (L2/10-029) — Anshuman Pandey ( L2/10-050)

2010-01-29 Govt. of India’s inputs on document no. L2/10-029 — Swaran Lata ( L2/10-051)

2010-02-02 Updated property classification for Brahmi-derived scripts — Ken Whistler ( L2/10-056)

2010-09-01 Proposal to encode the Indian Rupee Symbol in the UCS — Gov't of India / Swaran Lata ( WG2 N3887,  L2/10-258)

2010-11-27 Comments on Devanagari short vowels — Shriramana Sharma ( L2/10-471)

2011-01-21 Diacritic Marks for Short e & o Vowels (Dravidian and Vedic) in Devanagari (North India) and Grantha (South India) — Naga Ganesan ( L2/11-011)

2011-05-23 Proposal to Encode the Marwari Letter DDA for Devanagari — Anshuman Pandey ( WG2 N3970,  L2/10-475)

2011-07-28 A clear policy on encoding OM characters — Shriramana Sharma ( L2/11-308)

2011-10-21 Devanagari Vip Team: Variant Issues Report (replaces L2/11-334) — ICANN ( L2/11-370)

2012-03-17 Request for editorial updates to various Indic scripts — Shriramana Sharma ( L2/12-106)

2012-05-02 Further editorial updates for Indic — Shriramana Sharma ( L2/12-164)

2012-05-03 Proposal to Encode the Sign SIDDHAM for Devanagari — Anshuman Pandey ( WG2 N4260,  L2/12-123)

2012-07-31 Indic Scripts in Unicode — Eric Muller ( L2/12-289)

2012-11-08 Adding Devanagri, Bengali and Myanmar digits to Script Extensions — Roozbeh Pournader ( L2/12-376)

2013-04-25 Proposal to Encode the JAIN OM for Devanagari in ISO/IEC 10646 — Anshuman Pandey ( WG2 N4408,  L2/13-056)

2013-05-10 Letter from Gov't of India to Lisa Moore re recent documents — Rajendra Kumar ( L2/13-124)

2014-08-05 Status report on Script Extensions and Indic properties — Roozbeh Pournader ( L2/14-199)

2015-05-20 Script property of A8F1 COMBINING DEVANAGARI SIGN AVAGRAHA — Shriramana Sharma ( L2/15-162)

2015-05-20 Updates to Devanagari Sama Vedic informative aliases — Shriramana Sharma ( L2/15-164)

2015-05-21 Concerning A8E6 COMBINING DEVANAGARI DIGIT SIX — Shriramana Sharma ( L2/15-163)

2015-06-05 Proposal to encode A8FE DEVANAGARI SIGN SPACING ANUSVARA — Shriramana Sharma ( L2/15-178)

2015-12-07 Proposal to encode the Devanagari letter and vowel sign AY — Anshuman Pandey ( L2/15-335)

UTC #146 Minutes ( L2/16-004) (See D.7 for decision and action items)

2017-01-17 Preliminary proposal to encode Devanagari letter numerals — Srinidhi A, Sridatta A ( L2/17-010)

UTC #150 Minutes ( L2/17-016) (See D.4.1 for decision and action items)

2017-01-22 Feedback on preliminary proposal for Devanagari letter numerals — Shriramana Sharma ( L2/17-040)

2017-04-17 Request for editorial updates to Indic scripts — Srinidhi A, Sridatta A ( L2/17-098)

Recommendations to UTC #152 July-August 2017 on Script Proposals ( L2/17-255) (See point 7.)

2017-04-28 Clarification on Devanagari letter numerals — Srinidhi A, Sridatta A ( L2/17-116)

2017-05-08 On Devanagari letter numerals — Shriramana Sharma ( L2/17-159)