diff --git a/src/cpr_sdk/pipeline_general_models.py b/src/cpr_sdk/pipeline_general_models.py
index 0eb552b..ad1b3b2 100644
--- a/src/cpr_sdk/pipeline_general_models.py
+++ b/src/cpr_sdk/pipeline_general_models.py
@@ -2,7 +2,7 @@
 from enum import Enum
 from typing import Mapping, Any, List, Optional, Sequence, Union
 
-from pydantic import BaseModel, field_validator, model_validator
+from pydantic import BaseModel, field_validator
 
 Json = dict[str, Any]
 
@@ -29,7 +29,7 @@ class BackendDocument(BaseModel):
     family_import_id: str
     family_slug: str
     publication_ts: datetime
-    date: Optional[str] = None  # Set on import by a validator
+    date: Optional[str] = None  # Deprecated
     source_url: Optional[str] = None
     download_url: Optional[str] = None
     corpus_import_id: Optional[str] = None
@@ -45,20 +45,6 @@ class BackendDocument(BaseModel):
 
     metadata: Json
 
-    @model_validator(mode="after")
-    def convert_publication_ts_to_date(self):
-        """
-        Convert publication_ts to a datetime string.
-
-        This is necessary as OpenSearch expects a date object.
-
-        TODO: remove when no longer using Opensearch
-        """
-
-        self.date = self.publication_ts.strftime("%d/%m/%Y")
-
-        return self
-
     @field_validator("type", mode="before")
     @classmethod
     def none_to_empty_string(cls, value):
diff --git a/src/cpr_sdk/version.py b/src/cpr_sdk/version.py
index 9f91e53..2457b77 100644
--- a/src/cpr_sdk/version.py
+++ b/src/cpr_sdk/version.py
@@ -1,6 +1,6 @@
 _MAJOR = "1"
 _MINOR = "3"
-_PATCH = "10"
+_PATCH = "11"
 _SUFFIX = ""
 
 VERSION_SHORT = "{0}.{1}".format(_MAJOR, _MINOR)