Documentation: Update v3 migration docs (#12752)

docs/migration-v3.md

@@ -1,5 +1,9 @@
 # v3 Migration Guide
 
+## Pre-Requisites
+
+Upgrading to Paperless-ngx v3 can only be performed from version 2.20.15. If you are running an older version, please upgrade to v2.20.15 before proceeding with the v3 upgrade.
+
 ## Secret Key is Now Required
 
 The `PAPERLESS_SECRET_KEY` environment variable is now required. This is a critical security setting used for cryptographic signing and should be set to a long, random value.
@@ -37,6 +41,10 @@ separating the directory ignore from the file ignore.
 | `CONSUMER_IGNORE_PATTERNS`     | [`CONSUMER_IGNORE_PATTERNS`](configuration.md#PAPERLESS_CONSUMER_IGNORE_PATTERNS)   | **Now regex, not fnmatch**; user patterns are added to (not replacing) default ones  |
 | _New_                          | [`CONSUMER_IGNORE_DIRS`](configuration.md#PAPERLESS_CONSUMER_IGNORE_DIRS)           | Additional directories to ignore; user entries are added to (not replacing) defaults |
 
+## Duplicate Handling Changes
+
+Paperless-ngx v3 no longer rejects duplicate documents by default. Instead, it now allows duplicates but adds a way to identify them via the UI. To (re-)enable duplicate rejection, set `PAPERLESS_CONSUMER_DELETE_DUPLICATES=true` in your environment.
+
 ## Encryption Support
 
 Document and thumbnail encryption is no longer supported. This was previously deprecated in [paperless-ng 0.9.3](https://github.com/paperless-ngx/paperless-ngx/blob/dev/docs/changelog.md#paperless-ng-093)

src/paperless/checks.py

@@ -202,10 +202,10 @@ def check_v3_minimum_upgrade_version(
     **kwargs: object,
 ) -> list[Error]:
     """
-    Enforce that upgrades to v3 must start from v2.20.10.
+    Enforce that upgrades to v3 must start from v2.20.15.
 
     v3 squashes all prior migrations into 0001_squashed and 0002_squashed.
-    If a user skips v2.20.10, the data migration in 1075_workflowaction_order
+    If a user skips v2.20.15, the data migration in 1075_workflowaction_order
     never runs and the squash may apply schema changes against an incomplete
     database state.
     """
@@ -232,7 +232,7 @@ def check_v3_minimum_upgrade_version(
         if {"0001_squashed", "0002_squashed"} & applied:
             return []
 
-        # On v2.20.10 exactly — squash will pick up cleanly from here
+        # On v2.20.15 exactly — squash will pick up cleanly from here
         if "1075_workflowaction_order" in applied:
             return []
 
@@ -243,8 +243,8 @@ def check_v3_minimum_upgrade_version(
         Error(
             "Cannot upgrade to Paperless-ngx v3 from this version.",
             hint=(
-                "Upgrading to v3 can only be performed from v2.20.10."
-                "Please upgrade to v2.20.10, run migrations, then upgrade to v3."
+                "Upgrading to v3 can only be performed from v2.20.15."
+                "Please upgrade to v2.20.15, run migrations, then upgrade to v3."
                 "See https://docs.paperless-ngx.com/setup/#upgrading for details."
             ),
             id="paperless.E002",

src/paperless/tests/test_checks.py

@@ -584,11 +584,11 @@ class TestV3MinimumUpgradeVersionCheck:
     ) -> None:
         """
         GIVEN:
-            - DB is on an old v2 version (pre-v2.20.10)
+            - DB is on an old v2 version (pre-v2.20.15)
         WHEN:
             - The v3 upgrade check runs
         THEN:
-            - The error hint explicitly references v2.20.10 so users know what to do
+            - The error hint explicitly references v2.20.15 so users know what to do
         """
         mocker.patch.dict(
             "paperless.checks.connections",
@@ -596,7 +596,7 @@ class TestV3MinimumUpgradeVersionCheck:
         )
         result = check_v3_minimum_upgrade_version(None)
         assert len(result) == 1
-        assert "v2.20.10" in result[0].hint
+        assert "v2.20.15" in result[0].hint
 
     def test_db_error_is_swallowed(self, mocker: MockerFixture) -> None:
         """