SPF 2.0: Add backport version syntax

1 files changed, 16 insertions, 1 deletions

diff --git a/specs/spf-2.0/metadata.mdwn b/specs/spf-2.0/metadata.mdwn
index 9683fc6..dd0a749 100644
--- a/specs/spf-2.0/metadata.mdwn
+++ b/specs/spf-2.0/metadata.mdwn
@@ -129,7 +129,7 @@ Source Package Version Identifier [src-ver]
 
 In general, the syntax of source package version identifiers is:
 
-    <pkgver>[+sip<siprev>][-<pkgrev>][+<dist>~<distrev>]
+    <pkgver>[+sip<siprev>][-<pkgrev>][+<dist>~<distrev>][~bpu<distnum>+<bpurev>]
 
 `<pkgver>` is the version of the original upstream package or the native
 package.  It may only consist of lowercase Latin letters, digits, periods,
@@ -162,3 +162,18 @@ to `<dist>` of a new upstream package version, source archive repack, or
 distribution packaging revision.  It must be a string of one or more digits, the
 first of which must be greater than or equal to `1`.  (A regular expression for
 this is `[1-9][0-9]*`.)
+
+If the package is to be backported from `trunk` or another distribution into a
+different distribution other than `trunk`, the string `~bpu<distnum>+<bpurev>`
+must be included in the version identifier.  `<distnum>` is a numeric
+distribution version identifier for the distribution to which the package is
+backported.  It must be a string of one or more digits, the first of which must
+be greater than or equal to `1`.  (A regular expression for this is
+`[1-9][0-9]*`.)  `<bpurev>` is a number that should be incremented on each
+backport to distribution version `<distnum>` while `<pkgver>`, `<siprev>`,
+`<pkgrev>`, `<dist>`, and `<distrev>` remain constant.  It should be reset to
+`1` for the first backport to distribution version `<distnum>` of a new upstream
+package version, source archive repack, distribution packaging revision, or
+installation into a distribution other than `trunk`.  It must be a string of one
+or more digits, the first of which must be greater than or equal to `1`.  (A
+regular expression for this is `[1-9][0-9]*`.)