diff --git a/docs/history/changelog.md b/docs/history/changelog.md
index 66e41746b..e9b65ddd3 100644
--- a/docs/history/changelog.md
+++ b/docs/history/changelog.md
@@ -173,6 +173,7 @@ Per the [normative and non-normative content and changes policy](https://docs.go
     * `contracts.estimatedValue`
   * [#1372](https://github.com/open-contracting/standard/pull/1372) `Address.country`
   * [#1380](https://github.com/open-contracting/standard/pull/1380) [#1440](https://github.com/open-contracting/standard/pull/1440) `Document.languages`
+  * [#1439](https://github.com/open-contracting/standard/pull/1439) `Document.relatedItems`
 
 * Deprecate some fields:
   * [#1200](https://github.com/open-contracting/standard/pull/1200) `tender.submissionMethod`, because all codes from the `submissionMethod` codelist are deprecated.
diff --git a/schema/dereferenced-release-schema.json b/schema/dereferenced-release-schema.json
index 14a1f7346..6301df90e 100644
--- a/schema/dereferenced-release-schema.json
+++ b/schema/dereferenced-release-schema.json
@@ -1713,6 +1713,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -1944,6 +1957,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -5115,6 +5141,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -5346,6 +5385,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -7952,6 +8004,19 @@
                     "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                     "deprecatedVersion": "1.2"
                   }
+                },
+                "relatedItems": {
+                  "title": "Related items",
+                  "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                  "type": [
+                    "array",
+                    "null"
+                  ],
+                  "items": {
+                    "type": [
+                      "string"
+                    ]
+                  }
                 }
               },
               "patternProperties": {
@@ -9992,6 +10057,19 @@
                     "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                     "deprecatedVersion": "1.2"
                   }
+                },
+                "relatedItems": {
+                  "title": "Related items",
+                  "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                  "type": [
+                    "array",
+                    "null"
+                  ],
+                  "items": {
+                    "type": [
+                      "string"
+                    ]
+                  }
                 }
               },
               "patternProperties": {
@@ -12105,6 +12183,19 @@
                               "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                               "deprecatedVersion": "1.2"
                             }
+                          },
+                          "relatedItems": {
+                            "title": "Related items",
+                            "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                            "type": [
+                              "array",
+                              "null"
+                            ],
+                            "items": {
+                              "type": [
+                                "string"
+                              ]
+                            }
                           }
                         },
                         "patternProperties": {
@@ -12252,6 +12343,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -12552,6 +12656,19 @@
                           "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                           "deprecatedVersion": "1.2"
                         }
+                      },
+                      "relatedItems": {
+                        "title": "Related items",
+                        "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                        "type": [
+                          "array",
+                          "null"
+                        ],
+                        "items": {
+                          "type": [
+                            "string"
+                          ]
+                        }
                       }
                     },
                     "patternProperties": {
@@ -13461,6 +13578,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -13692,6 +13822,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -16863,6 +17006,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -17094,6 +17250,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -19696,6 +19865,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -21730,6 +21912,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -23843,6 +24038,19 @@
                             "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                             "deprecatedVersion": "1.2"
                           }
+                        },
+                        "relatedItems": {
+                          "title": "Related items",
+                          "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                          "type": [
+                            "array",
+                            "null"
+                          ],
+                          "items": {
+                            "type": [
+                              "string"
+                            ]
+                          }
                         }
                       },
                       "patternProperties": {
@@ -23990,6 +24198,19 @@
                       "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                       "deprecatedVersion": "1.2"
                     }
+                  },
+                  "relatedItems": {
+                    "title": "Related items",
+                    "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                    "type": [
+                      "array",
+                      "null"
+                    ],
+                    "items": {
+                      "type": [
+                        "string"
+                      ]
+                    }
                   }
                 },
                 "patternProperties": {
@@ -24290,6 +24511,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -26635,6 +26869,19 @@
                         "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                         "deprecatedVersion": "1.2"
                       }
+                    },
+                    "relatedItems": {
+                      "title": "Related items",
+                      "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                      "type": [
+                        "array",
+                        "null"
+                      ],
+                      "items": {
+                        "type": [
+                          "string"
+                        ]
+                      }
                     }
                   },
                   "patternProperties": {
@@ -26782,6 +27029,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -27012,6 +27272,19 @@
                   "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
                   "deprecatedVersion": "1.2"
                 }
+              },
+              "relatedItems": {
+                "title": "Related items",
+                "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
               }
             },
             "patternProperties": {
@@ -27153,6 +27426,19 @@
             "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
             "deprecatedVersion": "1.2"
           }
+        },
+        "relatedItems": {
+          "title": "Related items",
+          "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+          "type": [
+            "array",
+            "null"
+          ],
+          "items": {
+            "type": [
+              "string"
+            ]
+          }
         }
       },
       "patternProperties": {
diff --git a/schema/release-schema.json b/schema/release-schema.json
index e5c0d11cb..0a0b462b7 100644
--- a/schema/release-schema.json
+++ b/schema/release-schema.json
@@ -1129,6 +1129,19 @@
             "description": "This field is deprecated in favor of `languages`, to support documents in which multiple languages are used.",
             "deprecatedVersion": "1.2"
           }
+        },
+        "relatedItems": {
+          "title": "Related items",
+          "description": "The subset of items to which this document relates, expressed as the `id` values of the related entries in the parent object's `items` array. For example, an entry in the `tender.documents` array may be related only to entries in the `tender.items` array.",
+          "type": [
+            "array",
+            "null"
+          ],
+          "items": {
+            "type": [
+              "string"
+            ]
+          }
         }
       },
       "patternProperties": {
diff --git a/schema/versioned-release-validation-schema.json b/schema/versioned-release-validation-schema.json
index 991c744a3..500edda6b 100644
--- a/schema/versioned-release-validation-schema.json
+++ b/schema/versioned-release-validation-schema.json
@@ -1203,6 +1203,38 @@
               }
             }
           }
+        },
+        "relatedItems": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "properties": {
+              "releaseDate": {
+                "format": "date-time",
+                "type": "string"
+              },
+              "releaseID": {
+                "type": "string"
+              },
+              "value": {
+                "type": [
+                  "array",
+                  "null"
+                ],
+                "items": {
+                  "type": [
+                    "string"
+                  ]
+                }
+              },
+              "releaseTag": {
+                "type": "array",
+                "items": {
+                  "type": "string"
+                }
+              }
+            }
+          }
         }
       },
       "patternProperties": {