diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
index fd9289ede..f9600038b 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
@@ -527,7 +527,10 @@ public class AccountController {
   @PUT
   @Produces(MediaType.APPLICATION_JSON)
   @Path("/pin/")
-  public void setPin(@Auth Account account, @Valid DeprecatedPin accountLock) {
+  public void setPin(@Auth Account account, @Valid DeprecatedPin accountLock, @HeaderParam("User-Agent") String userAgent) {
+    // TODO Remove once PIN-based reglocks have been deprecated
+    logger.info("PIN set by User-Agent: {}", userAgent);
+
     account.setPin(accountLock.getPin());
     account.setRegistrationLock(null, null);
 
@@ -537,7 +540,10 @@ public class AccountController {
   @Timed
   @DELETE
   @Path("/pin/")
-  public void removePin(@Auth Account account) {
+  public void removePin(@Auth Account account, @HeaderParam("User-Agent") String userAgent) {
+    // TODO Remove once PIN-based reglocks have been deprecated
+    logger.info("PIN removed by User-Agent: {}", userAgent);
+
     account.setPin(null);
     accounts.update(account);
   }
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java
index 823160f44..3fd3cf256 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java
@@ -64,6 +64,7 @@ import org.whispersystems.textsecuregcm.auth.AmbiguousIdentifier;
 import org.whispersystems.textsecuregcm.auth.Anonymous;
 import org.whispersystems.textsecuregcm.auth.CombinedUnidentifiedSenderAccessKeys;
 import org.whispersystems.textsecuregcm.auth.OptionalAccess;
+import org.whispersystems.textsecuregcm.auth.StoredRegistrationLock;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicMessageRateConfiguration;
 import org.whispersystems.textsecuregcm.entities.AccountMismatchedDevices;
 import org.whispersystems.textsecuregcm.entities.AccountStaleDevices;
@@ -496,6 +497,11 @@ public class MessageController {
   public OutgoingMessageEntityList getPendingMessages(@Auth Account account, @HeaderParam("User-Agent") String userAgent) {
     assert account.getAuthenticatedDevice().isPresent();
 
+    // TODO Remove once PIN-based reglocks have been deprecated
+    if (account.getRegistrationLock().requiresClientRegistrationLock() && account.getRegistrationLock().hasDeprecatedPin()) {
+      logger.info("User-Agent with deprecated PIN-based registration lock: {}", userAgent);
+    }
+
     if (!Util.isEmpty(account.getAuthenticatedDevice().get().getApnId())) {
       RedisOperation.unchecked(() -> apnFallbackManager.cancel(account, account.getAuthenticatedDevice().get()));
     }
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/websocket/AuthenticatedConnectListener.java b/service/src/main/java/org/whispersystems/textsecuregcm/websocket/AuthenticatedConnectListener.java
index c735724d9..0098b4694 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/websocket/AuthenticatedConnectListener.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/websocket/AuthenticatedConnectListener.java
@@ -68,6 +68,11 @@ public class AuthenticatedConnectListener implements WebSocketConnectListener {
                                                                              context.getClient(),
                                                                              retrySchedulingExecutor);
 
+      // TODO Remove once PIN-based reglocks have been deprecated
+      if (account.getRegistrationLock().requiresClientRegistrationLock() && account.getRegistrationLock().hasDeprecatedPin()) {
+        log.info("User-Agent with deprecated PIN-based registration lock: {}", context.getClient().getUserAgent());
+      }
+
       openWebsocketCounter.inc();
       RedisOperation.unchecked(() -> apnFallbackManager.cancel(account, device));
 
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/MessageControllerTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/MessageControllerTest.java
index b0933f429..91d700146 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/MessageControllerTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/MessageControllerTest.java
@@ -70,6 +70,7 @@ import org.mockito.stubbing.Answer;
 import org.whispersystems.textsecuregcm.auth.AmbiguousIdentifier;
 import org.whispersystems.textsecuregcm.auth.DisabledPermittedAccount;
 import org.whispersystems.textsecuregcm.auth.OptionalAccess;
+import org.whispersystems.textsecuregcm.auth.StoredRegistrationLock;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfiguration;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicMessageRateConfiguration;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicRateLimitChallengeConfiguration;
@@ -484,6 +485,7 @@ class MessageControllerTest {
     OutgoingMessageEntityList messagesList = new OutgoingMessageEntityList(messages, false);
 
     when(messagesManager.getMessagesForDevice(eq(AuthHelper.VALID_UUID), eq(1L), anyString(), anyBoolean())).thenReturn(messagesList);
+    when(AuthHelper.VALID_ACCOUNT.getRegistrationLock()).thenReturn(mock(StoredRegistrationLock.class));
 
     OutgoingMessageEntityList response =
         resources.getJerseyTest().target("/v1/messages/")