diff --git a/CHANGELOG.md b/CHANGELOG.md
index 39309fe..bba74ba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to pyCOREPOS will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## v0.3.5 (2025-01-15)
+
+### Fix
+
+- add workaround to avoid missing schema columns
+
 ## v0.3.4 (2025-01-15)
 
 ### Fix
diff --git a/corepos/db/office_op/model.py b/corepos/db/office_op/model.py
index 6087f67..4d79e88 100644
--- a/corepos/db/office_op/model.py
+++ b/corepos/db/office_op/model.py
@@ -1039,12 +1039,11 @@ class MemberType(Base):
 
     ssi = sa.Column(sa.Boolean(), nullable=True)
 
-    ignoreSales = sa.Column(sa.Boolean(), nullable=True, default=False)
-    ignore_sales = orm.synonym('ignoreSales')
+    # nb. this must be added explicitly if DB is new enough
+    #ignore_sales = sa.Column('ignoreSales', sa.Boolean(), nullable=True, default=False)
 
-    # TODO: this was apparently added "recently" - isn't present in all DBs
-    # (need to figure out how to conditionally include it in model?)
-    # sales_code = sa.Column('salesCode', sa.Integer(), nullable=True)
+    # nb. this must be added explicitly if DB is new enough
+    #sales_code = sa.Column('salesCode', sa.Integer(), nullable=True)
 
     def __str__(self):
         return self.description or ""
@@ -1842,3 +1841,22 @@ class PurchaseOrderNote(Base):
 
     def __str__(self):
         return self.notes or ""
+
+
+# the rest of this is a workaround to deal with the fact that some
+# CORE databases have columns which others do not.  i had assumed that
+# all would be more or less the same but not so in practice.  so if
+# your DB *does* have these columns, you must invoke the function
+# below in order to merge them into your schema.  you should do this
+# on app startup and they'll be available normally from then on.
+
+RUNTIME = {'added_latest_columns': False}
+
+def use_latest_columns():
+    if RUNTIME['added_latest_columns']:
+        return
+
+    MemberType.ignore_sales = sa.Column('ignoreSales', sa.Boolean(), nullable=True, default=False)
+    MemberType.sales_code = sa.Column('salesCode', sa.Integer(), nullable=True)
+
+    RUNTIME['added_latest_columns'] = True
diff --git a/pyproject.toml b/pyproject.toml
index 143843f..2aaef92 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "pyCOREPOS"
-version = "0.3.4"
+version = "0.3.5"
 description = "Python Interface to CORE POS"
 readme = "README.md"
 authors = [{name = "Lance Edgar", email = "lance@edbob.org"}]