diff --git a/GeneticsCore/src/org/labkey/GeneticsCore/mhc/MhcTaskRef.java b/GeneticsCore/src/org/labkey/GeneticsCore/mhc/MhcTaskRef.java
index bd82b2327..01d1c6d19 100644
--- a/GeneticsCore/src/org/labkey/GeneticsCore/mhc/MhcTaskRef.java
+++ b/GeneticsCore/src/org/labkey/GeneticsCore/mhc/MhcTaskRef.java
@@ -11,6 +11,7 @@
 import org.labkey.api.data.CompareType;
 import org.labkey.api.data.Container;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.data.SimpleFilter;
 import org.labkey.api.data.TableInfo;
 import org.labkey.api.data.TableSelector;
@@ -97,7 +98,7 @@ public void setContainerUser(ContainerUser containerUser)
 
     public static void saveLastRun(Container container, Date jobStart)
     {
-        PropertyManager.PropertyMap map = PropertyManager.getWritableProperties(container, PROP_CATEGORY, true);
+        WritablePropertyMap map = PropertyManager.getWritableProperties(container, PROP_CATEGORY, true);
         if (jobStart != null)
         {
             map.put(lastRunTime, String.valueOf(jobStart.getTime()));
@@ -112,7 +113,7 @@ public static void saveLastRun(Container container, Date jobStart)
 
     private Date getLastRun(Container c)
     {
-        PropertyManager.PropertyMap map = PropertyManager.getWritableProperties(c, PROP_CATEGORY, true);
+        WritablePropertyMap map = PropertyManager.getWritableProperties(c, PROP_CATEGORY, true);
         return map.containsKey(lastRunTime) ? new Date(Long.parseLong(map.get(lastRunTime))) : null;
     }
 
diff --git a/mergesync/src/org/labkey/mergesync/MergeSyncController.java b/mergesync/src/org/labkey/mergesync/MergeSyncController.java
index 965387578..837ce017a 100644
--- a/mergesync/src/org/labkey/mergesync/MergeSyncController.java
+++ b/mergesync/src/org/labkey/mergesync/MergeSyncController.java
@@ -25,6 +25,7 @@
 import org.labkey.api.data.ContainerManager;
 import org.labkey.api.data.ConvertHelper;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.security.RequiresPermission;
 import org.labkey.api.security.ValidEmail;
 import org.labkey.api.security.permissions.AdminPermission;
@@ -55,7 +56,7 @@ public ApiResponse execute(EtlAdminForm form, BindException errors)
         {
             Map<String, Object> resultProperties = new HashMap<>();
 
-            PropertyManager.PropertyMap configMap = PropertyManager.getWritableProperties(MergeSyncManager.CONFIG_PROPERTY_DOMAIN, true);
+            WritablePropertyMap configMap = PropertyManager.getWritableProperties(MergeSyncManager.CONFIG_PROPERTY_DOMAIN, true);
 
             configMap.put(MergeSyncManager.DATA_SOURCE_PROP_NAME, form.getDataSourceName());
             configMap.put(MergeSyncManager.SCHEMA_PROP_NAME, form.getSchemaName());
diff --git a/mergesync/src/org/labkey/mergesync/MergeSyncManager.java b/mergesync/src/org/labkey/mergesync/MergeSyncManager.java
index bb5a0a96f..7c2ddfdec 100644
--- a/mergesync/src/org/labkey/mergesync/MergeSyncManager.java
+++ b/mergesync/src/org/labkey/mergesync/MergeSyncManager.java
@@ -17,14 +17,15 @@
 package org.labkey.mergesync;
 
 import org.apache.commons.lang3.time.DateUtils;
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.labkey.api.data.Container;
 import org.labkey.api.data.ContainerManager;
 import org.labkey.api.data.DbSchema;
 import org.labkey.api.data.DbSchemaType;
 import org.labkey.api.data.DbScope;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.security.User;
 import org.labkey.api.security.UserManager;
 import org.labkey.api.security.ValidEmail;
@@ -212,7 +213,7 @@ public Date getLastRun()
 
     public void setLastRun(Date date)
     {
-        PropertyManager.PropertyMap pm = PropertyManager.getWritableProperties(CONFIG_PROPERTY_DOMAIN, true);
+        WritablePropertyMap pm = PropertyManager.getWritableProperties(CONFIG_PROPERTY_DOMAIN, true);
         date = DateUtils.truncate(date, Calendar.MINUTE);  //always round to nearest minute
         pm.put(LAST_RUN_PROP_NAME, String.valueOf(date.getTime()));
         pm.save();
diff --git a/ogasync/src/org/labkey/ogasync/OGASyncController.java b/ogasync/src/org/labkey/ogasync/OGASyncController.java
index 6f319bd66..35879d15f 100644
--- a/ogasync/src/org/labkey/ogasync/OGASyncController.java
+++ b/ogasync/src/org/labkey/ogasync/OGASyncController.java
@@ -23,6 +23,7 @@
 import org.labkey.api.action.SpringActionController;
 import org.labkey.api.data.ContainerManager;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.security.RequiresPermission;
 import org.labkey.api.security.ValidEmail;
 import org.labkey.api.security.permissions.AdminPermission;
@@ -83,7 +84,7 @@ public ApiResponse execute(EtlAdminForm form, BindException errors)
         {
             Map<String, Object> resultProperties = new HashMap<>();
 
-            PropertyManager.PropertyMap configMap = PropertyManager.getWritableProperties(OGASyncManager.CONFIG_PROPERTY_DOMAIN, true);
+            WritablePropertyMap configMap = PropertyManager.getWritableProperties(OGASyncManager.CONFIG_PROPERTY_DOMAIN, true);
 
             if (form.getLabkeyUser() != null)
             {
diff --git a/ogasync/src/org/labkey/ogasync/OGASyncManager.java b/ogasync/src/org/labkey/ogasync/OGASyncManager.java
index cf49abef1..b4f9c36ea 100644
--- a/ogasync/src/org/labkey/ogasync/OGASyncManager.java
+++ b/ogasync/src/org/labkey/ogasync/OGASyncManager.java
@@ -24,6 +24,7 @@
 import org.labkey.api.data.DbSchemaType;
 import org.labkey.api.data.DbScope;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.data.TableInfo;
 import org.labkey.api.security.User;
 import org.labkey.api.security.UserManager;
@@ -349,7 +350,7 @@ public void validateSettings() throws IllegalArgumentException
 
     public void setLastRun(Date date)
     {
-        PropertyManager.PropertyMap pm = PropertyManager.getWritableProperties(CONFIG_PROPERTY_DOMAIN, true);
+        WritablePropertyMap pm = PropertyManager.getWritableProperties(CONFIG_PROPERTY_DOMAIN, true);
         pm.put(LAST_RUN_PROP_NAME, String.valueOf(date.getTime()));
         pm.save();
     }
diff --git a/onprc_ehr/src/org/labkey/onprc_ehr/ONPRC_EHRManager.java b/onprc_ehr/src/org/labkey/onprc_ehr/ONPRC_EHRManager.java
index e58afaa63..a52b0a70f 100644
--- a/onprc_ehr/src/org/labkey/onprc_ehr/ONPRC_EHRManager.java
+++ b/onprc_ehr/src/org/labkey/onprc_ehr/ONPRC_EHRManager.java
@@ -17,6 +17,7 @@
 
 import org.labkey.api.data.Container;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.query.Queryable;
 import org.labkey.api.security.User;
 import org.labkey.api.settings.LookAndFeelProperties;
@@ -103,7 +104,7 @@ public static ONPRC_EHRManager get()
 
     public void lockAnimalCreation(Container c, User u, Boolean lock, Integer startingId, Integer idCount)
     {
-        PropertyManager.PropertyMap map = PropertyManager.getWritableProperties(c, LOCK_PROP_KEY, true);
+        WritablePropertyMap map = PropertyManager.getWritableProperties(c, LOCK_PROP_KEY, true);
         map.put("lockedBy", u.getDisplayName(u));
         map.put("locked", lock.toString());
         map.put("lockDate", new SimpleDateFormat(LookAndFeelProperties.getInstance(c).getDefaultDateTimeFormat()).format(new Date()));
diff --git a/onprc_ehr/src/org/labkey/onprc_ehr/issues/RestrictedIssueProviderImpl.java b/onprc_ehr/src/org/labkey/onprc_ehr/issues/RestrictedIssueProviderImpl.java
index accbbb8c6..fdc119b09 100644
--- a/onprc_ehr/src/org/labkey/onprc_ehr/issues/RestrictedIssueProviderImpl.java
+++ b/onprc_ehr/src/org/labkey/onprc_ehr/issues/RestrictedIssueProviderImpl.java
@@ -5,6 +5,7 @@
 import org.labkey.api.data.Container;
 import org.labkey.api.data.ContainerManager;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.issues.Issue;
 import org.labkey.api.issues.RestrictedIssueProvider;
 import org.labkey.api.query.SimpleValidationError;
@@ -60,7 +61,7 @@ public void setRestrictedIssueListGroup(Container c, String issueDefName, @Nulla
 
     private void setPropertyValue(Container c, String issueDefName, String key, String value)
     {
-        PropertyManager.PropertyMap props = PropertyManager.getWritableProperties(c, getPropMapName(issueDefName), true);
+        WritablePropertyMap props = PropertyManager.getWritableProperties(c, getPropMapName(issueDefName), true);
         props.put(key, value);
         props.save();
     }
@@ -143,8 +144,8 @@ private boolean checkAccess(User user, @NotNull Issue issue, @Nullable Group gro
     @Override
     public void deleteProperties(Container c, String issueDefName)
     {
-        PropertyManager.PropertyMap properties = PropertyManager.getProperties(c, getPropMapName(issueDefName));
-        if (!properties.isEmpty())
+        WritablePropertyMap properties = PropertyManager.getWritableProperties(c, getPropMapName(issueDefName), false);
+        if (properties != null)
         {
             properties.delete();
         }
diff --git a/sla/src/org/labkey/sla/SLAController.java b/sla/src/org/labkey/sla/SLAController.java
index 89079d11a..2c79acb67 100644
--- a/sla/src/org/labkey/sla/SLAController.java
+++ b/sla/src/org/labkey/sla/SLAController.java
@@ -32,6 +32,7 @@
 import org.labkey.api.data.ContainerManager;
 import org.labkey.api.data.DbScope;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.data.SimpleFilter;
 import org.labkey.api.data.TableInfo;
 import org.labkey.api.data.TableSelector;
@@ -164,7 +165,7 @@ public ApiResponse execute(EtlAdminForm form, BindException errors)
         {
             Map<String, Object> resultProperties = new HashMap<>();
 
-            PropertyManager.PropertyMap configMap = PropertyManager.getWritableProperties(ETLRunnable.CONFIG_PROPERTY_DOMAIN, true);
+            WritablePropertyMap configMap = PropertyManager.getWritableProperties(ETLRunnable.CONFIG_PROPERTY_DOMAIN, true);
 
             boolean shouldReschedule = false;
             if (form.getLabkeyUser() != null)
@@ -193,8 +194,8 @@ public ApiResponse execute(EtlAdminForm form, BindException errors)
 
             configMap.save();
 
-            PropertyManager.PropertyMap rowVersionMap = PropertyManager.getWritableProperties(ETLRunnable.ROWVERSION_PROPERTY_DOMAIN, true);
-            PropertyManager.PropertyMap timestampMap = PropertyManager.getWritableProperties(ETLRunnable.TIMESTAMP_PROPERTY_DOMAIN, true);
+            WritablePropertyMap rowVersionMap = PropertyManager.getWritableProperties(ETLRunnable.ROWVERSION_PROPERTY_DOMAIN, true);
+            WritablePropertyMap timestampMap = PropertyManager.getWritableProperties(ETLRunnable.TIMESTAMP_PROPERTY_DOMAIN, true);
 
             if (form.getTimestamps() != null)
             {
diff --git a/sla/src/org/labkey/sla/etl/ETL.java b/sla/src/org/labkey/sla/etl/ETL.java
index f79d0378f..ba995fd5f 100644
--- a/sla/src/org/labkey/sla/etl/ETL.java
+++ b/sla/src/org/labkey/sla/etl/ETL.java
@@ -15,9 +15,10 @@
  */
 package org.labkey.sla.etl;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 
 import java.io.IOException;
 import java.util.concurrent.Executors;
@@ -164,7 +165,7 @@ public static boolean isRunning()
 
     private static void setEnabled(Boolean enabled)
     {
-        PropertyManager.PropertyMap pm = PropertyManager.getWritableProperties(ETLRunnable.CONFIG_PROPERTY_DOMAIN, true);
+        WritablePropertyMap pm = PropertyManager.getWritableProperties(ETLRunnable.CONFIG_PROPERTY_DOMAIN, true);
         pm.put(ENABLED_PROP_NAME, enabled.toString());
         pm.save();
     }
diff --git a/sla/src/org/labkey/sla/etl/ETLRunnable.java b/sla/src/org/labkey/sla/etl/ETLRunnable.java
index 32d98a098..350b65935 100644
--- a/sla/src/org/labkey/sla/etl/ETLRunnable.java
+++ b/sla/src/org/labkey/sla/etl/ETLRunnable.java
@@ -27,6 +27,7 @@
 import org.labkey.api.data.DbSchema;
 import org.labkey.api.data.DbScope;
 import org.labkey.api.data.PropertyManager;
+import org.labkey.api.data.PropertyManager.WritablePropertyMap;
 import org.labkey.api.data.SQLFragment;
 import org.labkey.api.data.SimpleFilter;
 import org.labkey.api.data.SqlExecutor;
@@ -827,7 +828,7 @@ boolean isEmpty(TableInfo tinfo) throws SQLException
     private void setLastTimestamp(String tableName, Long ts)
     {
         log.info(String.format("setting new baseline timestamp of %s on collection %s", new Date(ts.longValue()).toString(), tableName));
-        PropertyManager.PropertyMap pm = PropertyManager.getWritableProperties(TIMESTAMP_PROPERTY_DOMAIN, true);
+        WritablePropertyMap pm = PropertyManager.getWritableProperties(TIMESTAMP_PROPERTY_DOMAIN, true);
         pm.put(tableName, ts.toString());
         pm.save();
     }
@@ -865,7 +866,7 @@ private Long getOriginDataSourceCurrentTime() throws SQLException, BadConfigExce
      */
     private void setLastVersion(String tableName, byte[] version)
     {
-        PropertyManager.PropertyMap pm = PropertyManager.getWritableProperties(ROWVERSION_PROPERTY_DOMAIN, true);
+        WritablePropertyMap pm = PropertyManager.getWritableProperties(ROWVERSION_PROPERTY_DOMAIN, true);
         byte[] encoded = Base64.encodeBase64(version);
         try
         {