Describe supported Tarantool versions with limitations

README.md

@@ -8,6 +8,58 @@ The `CRUD` module allows to perform CRUD operations on the cluster.
 It also provides the `crud-storage` role for
 [Tarantool Cartridge](https://github.com/tarantool/cartridge).
 
+# Supported Tarantool versions
+
+CRUD features depends on Tarantool features like key_def, merger, UUID modules
+and JSON paths support, JSON path updates and absent nullable fields. We do our
+best to provide uniform support for all supported Tarantool version with help
+of compatibility layer, runtime feature detection etc. but anyway some
+Tarantool versions has limited support in CRUD.
+
+Please consult with a list below to choose a Tarantool version compatible with
+CRUD module before use:
+
+- 1.10: since 1.10.7-91 with limited merger <sup>1</sup> and
+  keydef<sup>2</sup> modules support, without UUID keys comparison, JSON path
+  indexes, JSON path updates and limited support of absent nullable fields.
+- 2.2: since 2.2.0-268 with limited merger module support, without UUID keys
+  comparison, JSON path indexes, JSON path updates and limited support of absent
+  nullable fields.
+- 2.3: since 2.3.2-99 without UUID keys comparison, JSON path indexes and
+  limited support of absent nullable fields.
+- 2.5: since 2.5.0-275 with key_def and merger modules and without JSON path
+  indexes and limited support of absent nullable fields.
+- 2.6: since 2.6.2-99 with limited support of absent nullable fields.
+- 2.7: since 2.7.1-102 with limited support of absent nullable fields.
+- 2.8: since 2.8.0-307
+
+1. Differences from the built-in merger module - https://github.com/tarantool/tuple-merger#backward-and-forward-compatibility-guarantees
+2. Differences from the built-in key_def module - https://github.com/tarantool/tuple-keydef#differences-from-the-built-in-module
+
+<details>
+  <summary>Support of features used by CRUD in Tarantool versions</summary>
+
+For more information see the table below that describes Tarantool's versions
+and features for what CRUD module depends on.
+
+| Branch | merger                  | tuple-merger | key_def      | tuple-keydef | UUID         | JSON paths  | JSON path updates | abs. nullable fields  |
+|--------|-------------------------|--------------|--------------|--------------|--------------|-------------|-------------------|-----------------------|
+| 1.10   | Unsupported             | 1.10.7-91    | Unsupported  | 1.10.7-85    | Unsupported  | Unsupported | Unsupported       | Partially<sup>2</sup>
+| 2.2    | Unsupported<sup>1</sup> | Unsupported  | All versions | Unsupported  | Unsupported  | Unsupported | Unsupported       | Partially<sup>2</sup>
+| 2.3    | 2.3.2-99<sup>1</sup>    | Unsupported  | All versions | Unsupported  | Unsupported  | Unsupported | 2.3.0-316         | Partially<sup>2</sup>
+| 2.5    | 2.5.0-275<sup>1</sup>   | 2.5.1-150    | All versions | 2.5.1-145    | All versions | Unsupported | All versions      | Partially<sup>2</sup>
+| 2.6    | All versions            | 2.6.0-193    | All versions | 2.6.0-188    | All versions | 2.6.2-99    | All versions      | Partially<sup>2</sup>
+| 2.7    | All versions            | All versions | All versions | All versions | All versions | 2.7.1-102   | All versions      | Partially<sup>2</sup>
+| 2.8    | All versions            | All versions | All versions | All versions | All versions | 2.8.0-113   | All versions      | 2.8.0-307
+
+1. Module merger has been added in 2.2.0-268-gc7915eccd, however support was
+   limited due to [#4954](https://github.com/tarantool/tarantool/issues/4954).
+2. Absent nullable fields partially supported for 1.10+,
+   see [6c30483](https://github.com/tarantool/tarantool/commit/e17a53843fa19603213d5a0f4d08750335223436)
+   and [Add intermediate nullable fields on update if not present in tuple](https://github.com/tarantool/crud/issues/113).
+
+</details>
+
 ## API
 
 The CRUD operations should be called from router.