Acrobat Reader 1.0 for Macintosh was originally released 15 June 1993, later for DOS and Windows 3.1. This was not available in single copies and was not initially free. After a while the IRS purchased a right to distribute Reader 1.0, effectively making it seem free to those who obtained it that way:
PDF version 1.0 supported.
Acrobat Exchange 1.0 (included PDFWriter printer driver and Acrobat Exchange application).
Acrobat Distiller 1.0. Created a PDF from PostScript (no printer driver at this stage).
Acrobat Reader 2.0 for Windows and Macintosh was first released September 1994. It is now available free of charge:
PDF version 1.1 (and prior) supported.
Acrobat Exchange 2.0, package as 1.0.
Acrobat Professional 2.0, which included the contents of Acrobat Exchange, plus Distiller.
There were 2.1 updates.
Acrobat Catalog was introduced, using Verity, Inc. technology to create searchable indexes to PDF files. Searching required a special version of Acrobat Reader or Acrobat Exchange.
Acrobat Reader 3.0 was released 1996. The first to display PDF files in-browser, and the first to support form filling:
PDF version 1.2 (and prior) supported.
A free Reader to allow searching was made available, but was not part of the default download.
Acrobat 3.0: replaced Acrobat Professional 2.1. Included Acrobat Catalog, and a Distiller printer driver.
First release with support for Windows 95 and later. Last release with support for Windows 3.1.
Acrobat Reader 4.0 was released April 1999:
PDF version 1.3 (and prior) supported. Added support for PKI and digital signatures via plug-ins.
Updates to 4.05.
Introduced Distiller Server 4.0, identical to the regular Distiller but with a multi-user license (Windows, Linux, Solaris).
Acrobat Business Tools 4.0: a limited version of Acrobat.
Acrobat Reader 5.0 was released May 2001:
PDF version 1.4 (and prior) supported.
Acrobat 5.0. PDFWriter removed from Macintosh application
Updates to 5.0.5. Acrobat 5.0.5 was the first to be able to run native in Mac OS X, but also ran in Mac OS 9.
Distiller Server 5.0.
Acrobat Approval 5.0: a limited version of Acrobat, mainly sold to people who wanted to digitally sign or save fill in forms.
Acrobat Reader 5.1: supported the Adobe LiveCycle Reader Extensions (e.g. forms saving) (which was then under a different name).
Adobe Reader 6.0 was released April 2003. No Linux or Unix versions were released:
PDF version 1.5 (and prior) supported. Added support for PKI via Microsoft Windows CryptoAPI without plug-in.
Acrobat Professional 6.0: replacement for Acrobat 5.0, with new features. Distiller printer driver renamed Adobe PDF. PDFWriter now gone for good. New version of Catalog integrated and not compatible with earlier products for searching.
Acrobat Standard 6.0: limited version of Acrobat Professional, including Distiller but lacking features including Catalog, form design, prepress support.
Updates to 6.0.1, 6.0.2, 6.0.3, 6.0.4, 6.0.5 and 6.0.6
Dropped support for Windows 95 and Windows 98 First Edition. Acrobat Standard was for Windows 98 Second Edition, Me, NT 4.0 SP6, 2000 SP2, and XP only. The professional version dropped support for Windows 98 SE and ME. Version 6.0 also dropped support for Mac OS 9 and earlier. It was the first release for Mac OS X.
Distiller Server 6.0.
Acrobat Elements 6.0: PDF creation only, aimed at the corporate market (minimum 1000 licenses, Windows only)
Acrobat Elements Server 6.0: client/server version of Acrobat Elements
Technology for "Reader enabling", allowing Reader to save, sign or annotate PDF files if the licensee had enabled the files.