diff --git a/docs/specs/editions.md b/docs/specs/editions.md
new file mode 100644
index 00000000000..bfe0bd38e12
--- /dev/null
+++ b/docs/specs/editions.md
@@ -0,0 +1,60 @@
+# Editions
+
+Vortex defines an evergrowing set of serializable array encodings, once written this can be read back by any future
+version of vortex.
+**Editions** are used to keep track of these encodings and talk about groups of encodings.
+
+The edition `core2026.07.0` (coming soon) is the first such edition containing all encodings currently
+enabled by the writer.
+Editions are additive so an edition that comes after a previous one contains all the encodings from the previous one
+and more.
+The writer can be configured with a set of different editions (e.g. `core2026.07.0` and `unstable2026.05.0` all stable
+encoding released before July 2026 and all unstable encodings from May 2026).
+
+Editions can be used to constrain your minimum required vortex reader, since latest version over vortex across all
+editions is the earliest version of vortex required to read that file.
+
+## Resolving an unknown-encoding error
+
+If a read failed with an unknown encoding ID and pointed you here, the reader met an encoding
+it does not support. Find the encoding ID in the [registry](#edition-registry) below:
+
+1. **The ID is listed under an edition.** The file is newer than your Vortex build. Upgrade to
+   at least that edition's required Vortex release and the file will read.
+2. **The ID is not listed anywhere.** The file was written outside the editions system, with a
+   custom, third-party, or experimental encoding. Ask the producer of the file how to read it,
+   or register the encoding with your session before reading. Tools that only inspect or
+   relocate data (rather than query it) can opt in to `allow_unknown`, which decodes
+   unrecognised encodings into inert placeholders.
+
+## Writing with an edition
+
+The default the writer targets a `core` edition lagging the latest vortex release by a few version giving delay before
+writing the latest vortex encodings to disk.
+Every file you write carries the read-forever guarantee. If a file would contain an encoding
+outside the targeted edition, the write fails immediately; edition violations never surface as
+someone else's read error later.
+
+Two knobs exist when the default is not what you want:
+
+- **Pin an older edition** when files must stay readable by deployments running older Vortex.
+- **Opt in to additional edition families.** Editions come in independently versioned,
+  additive families — `core` today, with families for more specialised encoding groups (for
+  example spatial encodings) possible later. A writer targets at most one edition per family
+  and may emit any encoding in their union; each encoding belongs to exactly one family.
+
+You can also opt out of editions entirely to write custom or experimental encodings. Doing so
+is an explicit choice that gives up the standardization guarantee — only readers that know your
+encodings can read those files.
+
+## How editions change
+
+A published edition is frozen — its encoding list never grows or shrinks. New encodings are
+staged in a **draft** edition and become guaranteed only when that draft is frozen as the next
+edition; each encoding's registry entry records the edition it joined in. In the future an
+encoding may be *deprecated*, meaning writers stop emitting it — but readers keep decoding it
+indefinitely, so deprecation never invalidates existing files.
+
+## Edition registry
+
+Coming soon..
\ No newline at end of file
diff --git a/docs/specs/file-format.md b/docs/specs/file-format.md
index 425294f2d99..b9ce8da2eed 100644
--- a/docs/specs/file-format.md
+++ b/docs/specs/file-format.md
@@ -17,7 +17,9 @@ definition that allows efficiently querying the layout.
 
 Other considerations for the Vortex file format include:
 
-* Backwards compatibility, and (coming soon) forwards compatibility.
+* Backwards compatibility, and (coming soon) forwards compatibility. The set of encodings a
+  writer may put in a file — and the resulting read-compatibility promise — is governed by
+  [Editions](/specs/editions).
 * Fine-grained encryption.
 * Efficient access for both local disk and cloud storage.
 * Minimal overhead reading few columns or rows from wide or long arrays.
diff --git a/docs/specs/index.md b/docs/specs/index.md
index 045ccb0710d..12fab8da430 100644
--- a/docs/specs/index.md
+++ b/docs/specs/index.md
@@ -8,6 +8,7 @@ maxdepth: 2
 ---
 
 file-format
+editions
 ipc-format
 dtype-format
 scalar-format