.. SPDX-License-Identifier: CC-BY-4.0
   Copyright 2026 The Linux Foundation

``+`` Expressions
=================

Use a ``+`` operator to indicate that the recipient may comply with *either* the specified license, *or* with any later version of it.

For example:

``# SPDX-License-Identifier: EPL-1.0+``

indicates that the recipient may comply with *either* `EPL-1.0 <https://spdx.org/licenses/EPL-1.0.html>`__, *or* `EPL-2.0 <https://spdx.org/licenses/EPL-2.0.html>`__ (or, presumably, with any other version that might be published by the license steward in the future).

Some licenses have been published by their license steward in a series of subsequent versions. The SPDX project does not track or indicate *which* licenses may be considered "later versions" of other ones. Making that determination is up to users of the SPDX metadata to determine for themselves, as with any other license compliance decisions.

Special case for GPL family of licenses
---------------------------------------

`As requested by the FSF <https://www.gnu.org/licenses/identify-licenses-clearly.html>`__, licenses in the GNU family of licenses (e.g. LGPL, GPL, AGPL, GFDL) are not recommended to use the ``+`` operators. Instead, these license identifiers use an ``-only`` or ``-or-later`` suffix.

For example:

``# SPDX-License-Identifier: GPL-2.0-only``

indicates that the recipient should comply with verson 2 of the GPL; but

``# SPDX-License-Identifier: GPL-2.0-or-later``

indicates that the recipient may choose to comply with *either* version 2 or version 3 of the GPL (or, presumably, with any other version that might be published by the license steward in the future).

Use of the standard ``+`` operators and the license IDs without these suffixes (e.g. ``GPL-2.0+``) is syntactically correct, though considered deprecated.