diff --git a/Example/Core/Tests/FIRLoggerTest.m b/Example/Core/Tests/FIRLoggerTest.m
index 797a133cdd..7f9e1a783c 100644
--- a/Example/Core/Tests/FIRLoggerTest.m
+++ b/Example/Core/Tests/FIRLoggerTest.m
@@ -76,15 +76,9 @@ static NSString *const kMessageCode = @"I-COR000001";
   XCTAssertEqualObjects(kFIRLoggerABTesting, @"[Firebase/ABTesting]");
   XCTAssertEqualObjects(kFIRLoggerAdMob, @"[Firebase/AdMob]");
   XCTAssertEqualObjects(kFIRLoggerAnalytics, @"[Firebase/Analytics]");
-  XCTAssertEqualObjects(kFIRLoggerAuth, @"[Firebase/Auth]");
   XCTAssertEqualObjects(kFIRLoggerCore, @"[Firebase/Core]");
-  XCTAssertEqualObjects(kFIRLoggerDatabase, @"[Firebase/Database]");
-  XCTAssertEqualObjects(kFIRLoggerDynamicLinks, @"[Firebase/DynamicLinks]");
-  XCTAssertEqualObjects(kFIRLoggerInstanceID, @"[Firebase/InstanceID]");
   XCTAssertEqualObjects(kFIRLoggerMLKit, @"[Firebase/MLKit]");
-  XCTAssertEqualObjects(kFIRLoggerMessaging, @"[Firebase/Messaging]");
   XCTAssertEqualObjects(kFIRLoggerRemoteConfig, @"[Firebase/RemoteConfig]");
-  XCTAssertEqualObjects(kFIRLoggerStorage, @"[Firebase/Storage]");
 }
 
 - (void)testInitializeASLForNonDebugMode {
diff --git a/Example/Podfile b/Example/Podfile
index 251a70e4c0..93886d48f0 100644
--- a/Example/Podfile
+++ b/Example/Podfile
@@ -19,7 +19,7 @@ target 'Core_Example_iOS' do
   # The next line is the forcing function for the Firebase pod. The Firebase
   # version's subspecs should depend on the component versions in their
   # corresponding podspec's.
-  pod 'Firebase/CoreOnly', '5.20.990'
+  pod 'Firebase/CoreOnly', '5.20.991'
 
   target 'Core_Tests_iOS' do
     inherit! :search_paths
diff --git a/Firebase/Core/FIRLogger.m b/Firebase/Core/FIRLogger.m
index 7fe3019630..6994a10769 100644
--- a/Firebase/Core/FIRLogger.m
+++ b/Firebase/Core/FIRLogger.m
@@ -20,21 +20,16 @@
 
 #import "Private/FIRVersion.h"
 
+FIRLoggerService kFIRLoggerCore = @"[Firebase/Core]";
+
+// All the FIRLoggerService definitions should be migrated to clients. Do not add new ones!
 FIRLoggerService kFIRLoggerABTesting = @"[Firebase/ABTesting]";
 FIRLoggerService kFIRLoggerAdMob = @"[Firebase/AdMob]";
 FIRLoggerService kFIRLoggerAnalytics = @"[Firebase/Analytics]";
 FIRLoggerService kFIRLoggerAuth = @"[Firebase/Auth]";
-FIRLoggerService kFIRLoggerCore = @"[Firebase/Core]";
-FIRLoggerService kFIRLoggerDatabase = @"[Firebase/Database]";
-FIRLoggerService kFIRLoggerDynamicLinks = @"[Firebase/DynamicLinks]";
-FIRLoggerService kFIRLoggerFirestore = @"[Firebase/Firestore]";
-FIRLoggerService kFIRLoggerInstanceID = @"[Firebase/InstanceID]";
 FIRLoggerService kFIRLoggerMLKit = @"[Firebase/MLKit]";
-FIRLoggerService kFIRLoggerMessaging = @"[Firebase/Messaging]";
 FIRLoggerService kFIRLoggerPerf = @"[Firebase/Performance]";
 FIRLoggerService kFIRLoggerRemoteConfig = @"[Firebase/RemoteConfig]";
-FIRLoggerService kFIRLoggerStorage = @"[Firebase/Storage]";
-FIRLoggerService kFIRLoggerSwizzler = @"[FirebaseSwizzlingUtilities]";
 
 /// Arguments passed on launch.
 NSString *const kFIRDisableDebugModeApplicationArgument = @"-FIRDebugDisabled";
diff --git a/Firebase/Core/Private/FIRLogger.h b/Firebase/Core/Private/FIRLogger.h
index f9523ab5e9..41f37480b8 100644
--- a/Firebase/Core/Private/FIRLogger.h
+++ b/Firebase/Core/Private/FIRLogger.h
@@ -30,16 +30,9 @@ extern FIRLoggerService kFIRLoggerAdMob;
 extern FIRLoggerService kFIRLoggerAnalytics;
 extern FIRLoggerService kFIRLoggerAuth;
 extern FIRLoggerService kFIRLoggerCore;
-extern FIRLoggerService kFIRLoggerDatabase;
-extern FIRLoggerService kFIRLoggerDynamicLinks;
-extern FIRLoggerService kFIRLoggerFirestore;
-extern FIRLoggerService kFIRLoggerInstanceID;
 extern FIRLoggerService kFIRLoggerMLKit;
-extern FIRLoggerService kFIRLoggerMessaging;
 extern FIRLoggerService kFIRLoggerPerf;
 extern FIRLoggerService kFIRLoggerRemoteConfig;
-extern FIRLoggerService kFIRLoggerStorage;
-extern FIRLoggerService kFIRLoggerSwizzler;
 
 /**
  * The key used to store the logger's error count.
diff --git a/Firebase/Database/Utilities/FUtilities.h b/Firebase/Database/Utilities/FUtilities.h
index f7fe7a5445..2f2c154fa2 100644
--- a/Firebase/Database/Utilities/FUtilities.h
+++ b/Firebase/Database/Utilities/FUtilities.h
@@ -15,6 +15,8 @@
  */
 
 #import <Foundation/Foundation.h>
+#import <FirebaseCore/FIRLogger.h>
+
 #import "FParsedUrl.h"
 
 @interface FUtilities : NSObject
@@ -70,6 +72,7 @@ FOUNDATION_EXPORT NSString *const kFPersistenceLogTag;
   } \
 } while(0)
 
+extern FIRLoggerService kFIRLoggerDatabase;
 BOOL FFIsLoggingEnabled(FLogLevel logLevel);
 void firebaseUncaughtExceptionHandler(NSException *exception);
 void firebaseJobsTroll(void);
diff --git a/Firebase/Database/Utilities/FUtilities.m b/Firebase/Database/Utilities/FUtilities.m
index d0a9a437fb..21704ca9ee 100644
--- a/Firebase/Database/Utilities/FUtilities.m
+++ b/Firebase/Database/Utilities/FUtilities.m
@@ -27,6 +27,7 @@
 #pragma mark -
 #pragma mark C functions
 
+FIRLoggerService kFIRLoggerDatabase = @"[Firebase/Database]";
 static FLogLevel logLevel = FLogLevelInfo; // Default log level is info
 static NSMutableDictionary* options = nil;
 
diff --git a/Firebase/DynamicLinks/Logging/FDLLogging.m b/Firebase/DynamicLinks/Logging/FDLLogging.m
index 1e6934fa43..ca968d6cfc 100644
--- a/Firebase/DynamicLinks/Logging/FDLLogging.m
+++ b/Firebase/DynamicLinks/Logging/FDLLogging.m
@@ -18,6 +18,8 @@
 
 #ifdef GIN_SCION_LOGGING
 #import <FirebaseCore/FIRLogger.h>
+
+FIRLoggerService kFIRLoggerDynamicLinks = @"[Firebase/DynamicLinks]";
 #endif  // GIN_SCION_LOGGING
 
 #ifdef GIN_SCION_LOGGING
diff --git a/Firebase/Messaging/FIRMessagingLogger.m b/Firebase/Messaging/FIRMessagingLogger.m
index 62eb8dae33..d3c96d2113 100644
--- a/Firebase/Messaging/FIRMessagingLogger.m
+++ b/Firebase/Messaging/FIRMessagingLogger.m
@@ -18,6 +18,8 @@
 
 #import <FirebaseCore/FIRLogger.h>
 
+FIRLoggerService kFIRLoggerMessaging = @"[Firebase/Messaging]";
+
 @implementation FIRMessagingLogger
 
 + (instancetype)standardLogger {
diff --git a/FirebaseCore.podspec b/FirebaseCore.podspec
index 9689dbe101..c3f7f368b8 100644
--- a/FirebaseCore.podspec
+++ b/FirebaseCore.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'FirebaseCore'
-  s.version          = '5.4.90'
+  s.version          = '5.4.91'
   s.summary          = 'Firebase Core for iOS (plus community support for macOS and tvOS)'
 
   s.description      = <<-DESC
diff --git a/Firestore/Example/Podfile b/Firestore/Example/Podfile
index 5085ca47c9..e0b8a0758e 100644
--- a/Firestore/Example/Podfile
+++ b/Firestore/Example/Podfile
@@ -14,7 +14,7 @@ target 'Firestore_Example_iOS' do
   # The next line is the forcing function for the Firebase pod. The Firebase
   # version's subspecs should depend on the component versions in their
   # corresponding podspec's.
-  pod 'Firebase/CoreOnly', '5.20.990'
+  pod 'Firebase/CoreOnly', '5.20.991'
 
   pod 'FirebaseAuth', :path => '../../'
   pod 'FirebaseAuthInterop', :path => '../../'
diff --git a/Firestore/core/src/firebase/firestore/util/log_apple.mm b/Firestore/core/src/firebase/firestore/util/log_apple.mm
index f1745e204c..808dac9244 100644
--- a/Firestore/core/src/firebase/firestore/util/log_apple.mm
+++ b/Firestore/core/src/firebase/firestore/util/log_apple.mm
@@ -32,6 +32,8 @@ namespace util {
 
 namespace {
 
+const FIRLoggerService kFIRLoggerFirestore = @"[Firebase/Firestore]";
+
 // Translates a C++ LogLevel to the equivalent Objective-C FIRLoggerLevel
 FIRLoggerLevel ToFIRLoggerLevel(LogLevel level) {
   switch (level) {