# Language Standards Conformance

The Fortran standard has undergone several revisions since its initial publication as FORTRAN 66 (also known as FORTRAN IV). Subsequent revisions have been FORTRAN 77, Fortran 90, Fortran 95, Fortran 2003, Fortran 2008, and Fortran 2018. Each revision has added new features; some revisions have labeled features as "deprecated" (or obsolescent) or they have removed them. Intel® Fortran continues to support deprecated and deleted features.

Intel® Fortran conforms to the Fortran 2018 standard (ISO/IEC 1539-1:2018), Fortran 2008 standard (ISO/IEC 1539-1:2010), Fortran 2003 standard (ISO/IEC 1539-1:2004), American National Standard Fortran 95 (ANSI X3J3/96-007)1, and American National Standard Fortran 90 (ANSI X3.198-1992).2

The Fortran Standards committee is currently answering questions of interpretation on Fortran 2018 language features. Any answers given by the committee that are related to features implemented in Intel® Fortran may result in changes in future releases of the Intel® Fortran Compiler, even if the changes produce incompatibilities with earlier releases of Intel® Fortran.

Intel Fortran provides a number of extensions to the Fortran 2018 Standard. In the language reference, extensions (non-standard features) are displayed in this color.

Intel® Fortran also includes support for programs that conform to the previous Fortran standards (ANSI X3.9-1978 and ANSI X3.0-1966), the International Standards Organization standard ISO 1539-1980 (E), the Federal Information Processing Institute standard FIPS 69-1, and the Military Standard 1753 Language Specification.

Parent topic: Conformance, Compatibility, and Fortran Features

1 This is the same as International Standards Organization standard ISO/IEC 1539-1:1997 (E).

2 This is the same as International Standards Organization standard ISO/IEC 1539:1991 (E).