diff --git a/README.md b/README.md
index 52bd35cd..51da45bb 100644
--- a/README.md
+++ b/README.md
@@ -53,3 +53,6 @@ see the README in that folder for more details.
 ## Gen3 graph data flow
 
 <img src="docs/Gen3 graph data flow.png" width="70%">
+
+## Submitter ID
+Sheepdog requires the `submitter_id` to be unique per node per project. It means that, the `submitter_id` of all `case` nodes must be unique per project. This constraint was technically enforced by the unique index of `(project_id, submitter_id)` in every node table.
diff --git a/poetry.lock b/poetry.lock
index 43d81868..43a55d2a 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -663,13 +663,12 @@ psqlgraph = ">=3.0.0"
 
 [[package]]
 name = "dictionaryutils"
-version = "3.4.5"
+version = "3.4.6"
 description = "Python wrapper and metaschema for datadictionary."
-category = "main"
 optional = false
 python-versions = ">=3.6,<3.10"
 files = [
-    {file = "dictionaryutils-3.4.5.tar.gz", hash = "sha256:3348b369a67a68690e020adb9add358c40327c97ec4917f460cf3ba5cd263696"},
+    {file = "dictionaryutils-3.4.6.tar.gz", hash = "sha256:b834bbb802d930fefae99ad155a0b07eef1a07f87c0b3aaef220dc20dda73a9c"},
 ]
 
 [package.dependencies]
diff --git a/pyproject.toml b/pyproject.toml
index 63a25b60..e14091de 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,7 +15,7 @@ authlib = "*" # let authutils decide which version we're using
 authutils = ">=6.0.0"
 boto = ">=2.39.0"
 datamodelutils = ">=1.0.0"
-dictionaryutils = ">=3.2.0"
+dictionaryutils = ">=3.4.6"
 envelopes = ">=0.4"
 # flask 2.2.0 removes `RequestContext.preserved` which we use in a workaround in `conftest.client`
 Flask = ">=1.1.1,<2.2.0"