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+<!-- Copyright verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root. -->
+
+## Errata
+
+### 2020-11-30: Document inconsistency
+This bug existed between 2020-08-28 and 2020-09-23.
+The following needs to happen to trigger the bug:
+
+* Visibility delay is non-zero.
+* A new config change is deployed that contains changes to proton.
+  This config snapshot is stored in the transaction log on the content node.
+* vespa-proton-bin is restarted, and as part of the prepare for restart step,
+  at least one attribute vector is not flushed to the current serial number.
+* Due to the bug, replay of the transaction log will fail to replay feed operations to attributes after replaying the config change.
+  The effect is that all attributes that were not flushed as part of prepare for restart
+  will not get any of the updates since the last time they were flushed.
+* If a document was previously removed, lid space compaction will move another document to that local document id.
+  Due to later missing updates as part of restarting we might see values from the removed document for some of the attributes.
+* When the problem attributes are later flushed this inconsistency will be permanent.
+
+Solution:
+* Upgrade Vespa to at least vespa-7.306.19-1.el7.x86_64.rpm.
+* Complete re-feed of the corpus.
+
+
+
+### 2020-11-30: Regression introduced in Vespa 7.141 may cause data loss or inconsistencies when using 'create: true' updates
+There exists a regression introduced in Vespa 7.141 where updates marked as `create: true` (i.e. create if missing)
+may cause data loss or undetected inconsistencies in certain edge cases.
+This regression was introduced as part of an optimization effort to greatly reduce the common-case overhead of updates
+when replicas are out of sync.
+
+Fixed in Vespa 7.157.9 and beyond.
+If running a version affected (7.141 up to and including 7.147) you are strongly advised to upgrade.
+
+See [#11686](https://github.com/vespa-engine/vespa/issues/11686) for details.