diff --git a/rattail_corepos/config.py b/rattail_corepos/config.py
index 75f8f76..bc3309b 100644
--- a/rattail_corepos/config.py
+++ b/rattail_corepos/config.py
@@ -24,6 +24,8 @@
 Rattail-COREPOS Config Extension
 """
 
+import warnings
+
 from rattail.config import ConfigExtension
 from rattail.db.config import get_engines
 
@@ -36,6 +38,11 @@ class RattailCOREPOSExtension(ConfigExtension):
 
     def configure(self, config):
 
+        # show deprecation warnings by default, when they occur in corepos
+        # (nb. rattail_corepos warnings are already shown, per rattail)
+        warnings.filterwarnings('default', category=DeprecationWarning,
+                                module=r'^corepos')
+
         # office_op
         from corepos.db.office_op import Session
         engines = get_engines(config, section='corepos.db.office_op')