diff --git a/Podfile b/Podfile
index 85d88303da..49e5f8b9ab 100644
--- a/Podfile
+++ b/Podfile
@@ -7,6 +7,8 @@ use_frameworks!
 # OWS Pods
 ###
 
+pod 'SwiftProtobuf', "1.7.0"
+
 pod 'SignalCoreKit', git: 'https://github.com/signalapp/SignalCoreKit.git', testspecs: ["Tests"]
 # pod 'SignalCoreKit', path: '../SignalCoreKit', testspecs: ["Tests"]
 
diff --git a/SignalServiceKit/src/Contacts/SignalRecipient.m b/SignalServiceKit/src/Contacts/SignalRecipient.m
index 977b7e4afb..ad3286702c 100644
--- a/SignalServiceKit/src/Contacts/SignalRecipient.m
+++ b/SignalServiceKit/src/Contacts/SignalRecipient.m
@@ -296,9 +296,6 @@ const NSUInteger SignalRecipientSchemaVersion = 1;
     OWSAssertDebug(address.isValid);
     OWSAssertDebug(transaction);
 
-    OWSLogVerbose(@"address: %@", address);
-    OWSLogFlush();
-
     SignalRecipient *_Nullable phoneNumberInstance = nil;
     SignalRecipient *_Nullable uuidInstance = nil;
     if (address.phoneNumber != nil) {
@@ -325,44 +322,28 @@ const NSUInteger SignalRecipientSchemaVersion = 1;
             // TODO: Should we clean up any state related to the discarded recipient?
 
             // We try to preserve the recipient that has a session.
-            BOOL hasSessionForUuid = [self.sessionStore containsAnyActiveSessionForAccountId:uuidInstance.accountId
-                                                                                 transaction:transaction];
-            BOOL hasSessionForPhoneNumber =
-                [self.sessionStore containsAnyActiveSessionForAccountId:phoneNumberInstance.accountId
-                                                            transaction:transaction];
+            NSNumber *_Nullable sessionIndexForUuid =
+                [self.sessionStore maxSessionSenderChainKeyIndexForAccountId:uuidInstance.accountId
+                                                                 transaction:transaction];
+            NSNumber *_Nullable sessionIndexForPhoneNumber =
+                [self.sessionStore maxSessionSenderChainKeyIndexForAccountId:phoneNumberInstance.accountId
+                                                                 transaction:transaction];
 
-            // We try to preserve the recipient that has the contact thread with the most interactions.
-            NSUInteger numberOfInteractionsWithUUID = 0;
-            TSThread *_Nullable contactThreadForUuid = [[AnyContactThreadFinder new] contactThreadForUUID:address.uuid
-                                                                                              transaction:transaction];
-            if (contactThreadForUuid != nil) {
-                numberOfInteractionsWithUUID = [contactThreadForUuid numberOfInteractionsWithTransaction:transaction];
-            }
-            NSUInteger numberOfInteractionsWithPhoneNumber = 0;
-            TSThread *_Nullable contactThreadForPhoneNumber =
-                [[AnyContactThreadFinder new] contactThreadForPhoneNumber:address.phoneNumber transaction:transaction];
-            if (contactThreadForPhoneNumber != nil) {
-                numberOfInteractionsWithPhoneNumber =
-                    [contactThreadForPhoneNumber numberOfInteractionsWithTransaction:transaction];
+            if (SSKDebugFlags.verboseSignalRecipientLogging) {
+                OWSLogInfo(@"phoneNumberInstance: %@", phoneNumberInstance);
+                OWSLogInfo(@"uuidInstance: %@", uuidInstance);
+                OWSLogInfo(@"sessionIndexForUuid: %@", sessionIndexForUuid);
+                OWSLogInfo(@"sessionIndexForPhoneNumber: %@", sessionIndexForPhoneNumber);
             }
 
-            OWSLogWarn(@"phoneNumberInstance: %@", phoneNumberInstance);
-            OWSLogWarn(@"uuidInstance: %@", uuidInstance);
-            OWSLogWarn(@"numberOfInteractionsWithUUID: %lu", (unsigned long)numberOfInteractionsWithUUID);
-            OWSLogWarn(@"numberOfInteractionsWithPhoneNumber: %lu", (unsigned long)numberOfInteractionsWithPhoneNumber);
-            OWSLogWarn(@"hasSessionForUuid: %d", hasSessionForUuid);
-            OWSLogWarn(@"hasSessionForPhoneNumber: %d", hasSessionForPhoneNumber);
-            BOOL shouldUseUuid = NO;
-            if (hasSessionForPhoneNumber && !hasSessionForUuid) {
-                shouldUseUuid = NO;
-            } else if (hasSessionForUuid && !hasSessionForPhoneNumber) {
-                shouldUseUuid = YES;
-            } else if (numberOfInteractionsWithPhoneNumber > numberOfInteractionsWithUUID) {
-                shouldUseUuid = NO;
-            } else {
-                // Default to retaining the UUID recipient.
-                shouldUseUuid = YES;
-            }
+            // We want to retain the phone number recipient if it
+            // has a session and the uuid recipient doesn't or if
+            // both have a session but the phone number recipient
+            // has seen more use.
+            //
+            // All things being equal, we default to retaining the
+            // UUID recipient.
+            BOOL shouldUseUuid = (sessionIndexForPhoneNumber.intValue <= sessionIndexForUuid.intValue);
             if (shouldUseUuid) {
                 OWSFailDebug(@"Discarding phone number recipient in favor of uuid recipient.");
                 existingInstance = uuidInstance;
diff --git a/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.h b/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.h
index 42946798ef..561326a2d0 100644
--- a/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.h
+++ b/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.h
@@ -28,7 +28,8 @@ NS_ASSUME_NONNULL_BEGIN
                          deviceId:(int)deviceId
                       transaction:(SDSAnyWriteTransaction *)transaction;
 
-- (BOOL)containsAnyActiveSessionForAccountId:(NSString *)accountId transaction:(SDSAnyReadTransaction *)transaction;
+- (nullable NSNumber *)maxSessionSenderChainKeyIndexForAccountId:(NSString *)accountId
+                                                     transaction:(SDSAnyReadTransaction *)transaction;
 
 - (void)deleteSessionForAddress:(SignalServiceAddress *)address
                        deviceId:(int)deviceId
diff --git a/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.m b/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.m
index c5242ef575..0c0f1b3edd 100644
--- a/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.m
+++ b/SignalServiceKit/src/Storage/AxolotlStore/SSKSessionStore.m
@@ -205,11 +205,13 @@ NS_ASSUME_NONNULL_BEGIN
         [self loadSessionForAccountId:accountId deviceId:deviceId transaction:transaction].sessionState.hasSenderChain;
 }
 
-- (BOOL)containsAnyActiveSessionForAccountId:(NSString *)accountId transaction:(SDSAnyReadTransaction *)transaction
+- (nullable NSNumber *)maxSessionSenderChainKeyIndexForAccountId:(NSString *)accountId
+                                                     transaction:(SDSAnyReadTransaction *)transaction
 {
     OWSAssertDebug(accountId.length > 0);
     OWSAssertDebug([transaction isKindOfClass:[SDSAnyReadTransaction class]]);
 
+    NSNumber *_Nullable result = nil;
     NSDictionary *_Nullable dictionary = [self.keyValueStore getObjectForKey:accountId transaction:transaction];
     for (id value in dictionary.allValues) {
         if (![value isKindOfClass:[SessionRecord class]]) {
@@ -218,12 +220,20 @@ NS_ASSUME_NONNULL_BEGIN
             continue;
         }
         SessionRecord *record = (SessionRecord *)value;
-        OWSLogVerbose(@"Record: %d.", record.sessionState.hasSenderChain);
+        if (SSKDebugFlags.verboseSignalRecipientLogging) {
+            OWSLogInfo(@"Record hasSenderChain: %d.", record.sessionState.hasSenderChain);
+        }
         if (record.sessionState.hasSenderChain) {
-            return YES;
+            int index = record.sessionState.senderChainKey.index;
+            if (SSKDebugFlags.verboseSignalRecipientLogging) {
+                OWSLogInfo(@"Record index: %d.", index);
+            }
+            if (result == nil || result.intValue < index) {
+                result = @(index);
+            }
         }
     }
-    return NO;
+    return result;
 }
 
 - (void)deleteSessionForContact:(NSString *)contactIdentifier
diff --git a/SignalServiceKit/src/Util/FeatureFlags.swift b/SignalServiceKit/src/Util/FeatureFlags.swift
index e99017f22f..823a07404e 100644
--- a/SignalServiceKit/src/Util/FeatureFlags.swift
+++ b/SignalServiceKit/src/Util/FeatureFlags.swift
@@ -309,4 +309,7 @@ public class DebugFlags: NSObject {
 
     @objc
     public static let verboseNotificationLogging = build.includes(.qa)
+
+    @objc
+    public static let verboseSignalRecipientLogging = build.includes(.qa)
 }