Daylight releases are numbered using the following scheme:

The "system number" (e.g. 3.xx, 4.xx) indicates completely different systems. Each system is a completely new design.

Major releases (e.g. 4.1x, 4.2x, 4.3x) contain new features and enhancements. Often, programs and databases from one major release aren't compatible with those from another.

Minor releases, or "updates" (e.g. 4.32, 4.33) are for bug fixes and minor additional features. They are also occasionally for adding new platforms (computers and/or operating-system version).

The first two releases of system 4 were called "4.1" and "4.2"; under the above-described scheme they would have been called "4.11" and "4.21". There were two additional releases of the "demo" tape, which would have been "4.22" and "4.23". Release 4.24 (October '92) was the first to use this new version-numbering scheme.

4.11 Dec 20 1991
First 4.x release: SunOS only.

4.21 Mar 20 1992
Second release: bug fixes, added SGI platform.

4.22 Summer 1992
Demo Tape update (applics and toolkits not affected). Updated the demo database: added clustering data to illustrate Daylight's clustering product.

4.23 Sep 22 1992
Demo Tape update (applications and toolkits not affected) Same as 4.22, but added workaround for a bug in the SGI X window system.

4.24 Oct 2 1992
Update: many bug fixes, some added features.

4.25 Nov 13 1992
SGI Toolkit Tape only; corrects incompatibility between versions of SGI IRIX Operating system. All other 4.24 SGI and Sun tapes are unaffected.

4.31 May 1 1993
Added Print Package, Merlin Toolkit. Many bug fixes and enhancements. Added support for VAX/VMS (Toolkits, servers, and some non-X-Windows programs). Added Thor and Merlin management utilities.

4.32 Jul 1 1993
Added Rubicon program and Rubicon Toolkit. Added support for HPUX on HP9000/7xx series, and for Solaris on Sun machines. Improved "man" pages and help-widget text files. A number of minor bug fixes.

4.33 Jan 28 1994
Improved merlinserver, thorserver, and Merlin and Thor Toolkits. Improved printing. A number of minor bug fixes. Restructured & added to "contrib" programs.

4.34 Feb 25 1994
Revamped clustering programs. Partial molecular fingerprint generation. Fixed bugs introduced in 4.33.

4.41b Nov 23 1994
Beta version of 4.41.

4.41b2 Feb 12 1995
Second beta version of 4.41.

4.41 Mar 17 1995
Databases of mixtures, "monomer" toolkit (CHUCKLES, CHORTLES, & CHARTS), Program-Object Toolkit, parallelized (multi-CPU) version of clustering, MCL.

4.42 Feb 2 1996
HTML Documentation, CGI application programs, record locking, thordestroy(1), Thor/Merlin messages, Thor/Merlin eviction, faster TDT merging, Merlin parallel SMARTS searches, better Merlin performance under heavy load, Merlin program objects.

4.42p1 Apr 2 1996
Merlinserver, Merlinsmartstalk, and Daytoolserver bugs fixed in this patch.

4.51 May 1 1997
Reaction Toolkit, reaction databases in Thor/Merlin, formal object properties, read-only (CDROM) databases, cross-referencing non-identifiers in THOR, Merlin "similarity as sub/superstructure", and more.

4.61a Feb 20 1998
Alpha version of 4.61 used at MUG '98.

4.61b May 5 1998
Beta version of 4.61.

4.61 Jul 15 1998
ClogP, bug fixes, Reaction Toolkit enhancements, Java tools.

4.62 Mar 5 1999
Bug fixes, Java tools.

4.71a Feb 22 2000
Alpha version of 4.71 used at MUG '00.

4.71b Winter/Spring 2000
Beta version of 4.71 featuring the Oracle Cartridge.

4.71 Aug 1 2000
Bug fixes, Java, Oracle cartridge, ClogP, 34-bit thorserver, daycgi fixes, SMILES fixes.

4.72 Mar 06 2001
Patch release: daycart on SGI and Linux, Daycart Solaris fixes, Javagrins fixes, ClogP fixes, smi2gif.

4.73 Nov 15 2001
Patch release: Bug fixes, printing, smi2gif, non-Java dayutilserver.

4.81 Dec 20 2002
Feature release: Daycart, toolkit, ClogP, http toolkit, licensing.

4.82 Jun 16 2003
Patch release: Bug fixes, depictions, property package, Daycart VCS functions.

4.83 Jan 26 2004
Patch release: Bug fixes, depictions, Daycart optimizer, new DayPerl, Windows Toolkits/Daycart.

4.91 April 8, 2005
Conversion tools, new clustering, new Daycart partitioning, reactions, searches, bug fixes.

4.92 April 17, 2006
Additional conversion tools, new Daycart similarity searches, FlexLM licensing.

4.93 April 9, 2007
New ClogP version, web services, Daycart performance improvments, multithreading toolkits, Java wrappers, common substructure, Solaris/x86.

4.94 February 1, 2008
Additional web services, performance and reliability improvements for Daycart, R-group conversion, RTable generation, png support.

4.95 August 1, 2011
Bug fixes, new ClogP version, performance and reliability improvements for Daycart/Oracle, new Daycart under Postgresql.