+ 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, or EPL-2.0 (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, 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.