diff --git a/Apptentive/Apptentive.xcodeproj/project.pbxproj b/Apptentive/Apptentive.xcodeproj/project.pbxproj
index b3c554305..ae20d2a50 100644
--- a/Apptentive/Apptentive.xcodeproj/project.pbxproj
+++ b/Apptentive/Apptentive.xcodeproj/project.pbxproj
@@ -78,6 +78,9 @@
 		01798C021EAF94FE00633164 /* ApptentivePayloadSender.h in Headers */ = {isa = PBXBuildFile; fileRef = 01798C001EAF94FD00633164 /* ApptentivePayloadSender.h */; };
 		01798C031EAF94FE00633164 /* ApptentivePayloadSender.m in Sources */ = {isa = PBXBuildFile; fileRef = 01798C011EAF94FD00633164 /* ApptentivePayloadSender.m */; };
 		017E54ED1F3B860E00EA9F81 /* ApptentiveJSONSerializationTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 017E54EC1F3B860E00EA9F81 /* ApptentiveJSONSerializationTests.m */; };
+		018E1CE021936B1400E58F33 /* ApptentiveEngagementTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 018E1CDF21936B1300E58F33 /* ApptentiveEngagementTests.swift */; };
+		018E1CE321936B6600E58F33 /* conversation-4.archive in Resources */ = {isa = PBXBuildFile; fileRef = 018E1CE121936B6600E58F33 /* conversation-4.archive */; };
+		018E1CE421936B6600E58F33 /* conversation-5.archive in Resources */ = {isa = PBXBuildFile; fileRef = 018E1CE221936B6600E58F33 /* conversation-5.archive */; };
 		018FAFDF1FC4A9C6007C52FE /* ApptentiveAndClause.h in Headers */ = {isa = PBXBuildFile; fileRef = 018FAFDD1FC4A9C6007C52FE /* ApptentiveAndClause.h */; };
 		018FAFE01FC4A9C6007C52FE /* ApptentiveAndClause.m in Sources */ = {isa = PBXBuildFile; fileRef = 018FAFDE1FC4A9C6007C52FE /* ApptentiveAndClause.m */; };
 		018FAFE31FC4AC41007C52FE /* ApptentiveOrClause.h in Headers */ = {isa = PBXBuildFile; fileRef = 018FAFE11FC4AC41007C52FE /* ApptentiveOrClause.h */; };
@@ -512,6 +515,9 @@
 		01798C001EAF94FD00633164 /* ApptentivePayloadSender.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ApptentivePayloadSender.h; sourceTree = "<group>"; };
 		01798C011EAF94FD00633164 /* ApptentivePayloadSender.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ApptentivePayloadSender.m; sourceTree = "<group>"; };
 		017E54EC1F3B860E00EA9F81 /* ApptentiveJSONSerializationTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ApptentiveJSONSerializationTests.m; sourceTree = "<group>"; };
+		018E1CDF21936B1300E58F33 /* ApptentiveEngagementTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ApptentiveEngagementTests.swift; sourceTree = "<group>"; };
+		018E1CE121936B6600E58F33 /* conversation-4.archive */ = {isa = PBXFileReference; lastKnownFileType = file.bplist; path = "conversation-4.archive"; sourceTree = "<group>"; };
+		018E1CE221936B6600E58F33 /* conversation-5.archive */ = {isa = PBXFileReference; lastKnownFileType = file.bplist; path = "conversation-5.archive"; sourceTree = "<group>"; };
 		018FAFDD1FC4A9C6007C52FE /* ApptentiveAndClause.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ApptentiveAndClause.h; sourceTree = "<group>"; };
 		018FAFDE1FC4A9C6007C52FE /* ApptentiveAndClause.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ApptentiveAndClause.m; sourceTree = "<group>"; };
 		018FAFE11FC4AC41007C52FE /* ApptentiveOrClause.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ApptentiveOrClause.h; sourceTree = "<group>"; };
@@ -1024,6 +1030,7 @@
 		01A2CF9E1E49062800C2103A /* ApptentiveTests */ = {
 			isa = PBXGroup;
 			children = (
+				01917D431E5E0B7400B37D82 /* ApptentiveTests-Bridging-Header.h */,
 				01201AD21FC637BD00EB3593 /* CodePointAndInteractionTests.m */,
 				EF4EABA22040A8C5003318C9 /* utils */,
 				01A2D20F1E4946D500C2103A /* data */,
@@ -1041,7 +1048,6 @@
 				01A2D2071E4946D500C2103A /* ApptentiveMigrationTests.m */,
 				01A2D2091E4946D500C2103A /* ApptentiveStyleSheetTests.m */,
 				01A2D20A1E4946D500C2103A /* ApptentiveSurveyTests.m */,
-				01917D431E5E0B7400B37D82 /* ApptentiveTests-Bridging-Header.h */,
 				01A2D20B1E4946D500C2103A /* ApptentiveUtilitiesTests.m */,
 				01917D441E5E0B7400B37D82 /* ConversationManagerTests.swift */,
 				01A2D20D1E4946D500C2103A /* CriteriaTests.h */,
@@ -1053,6 +1059,7 @@
 				0123005E20531698000EC3C3 /* ClauseTests.m */,
 				EF4EAB99203F9821003318C9 /* AppptentiveAsyncLogWriterTests.swift */,
 				012ED92B2072FABE003D87F3 /* RetryPolicyTests.swift */,
+				018E1CDF21936B1300E58F33 /* ApptentiveEngagementTests.swift */,
 			);
 			path = ApptentiveTests;
 			sourceTree = "<group>";
@@ -1645,6 +1652,8 @@
 		01A2D20F1E4946D500C2103A /* data */ = {
 			isa = PBXGroup;
 			children = (
+				018E1CE121936B6600E58F33 /* conversation-4.archive */,
+				018E1CE221936B6600E58F33 /* conversation-5.archive */,
 				EFF4D2A51EC37F0A00FD4EFE /* containers */,
 				01A2D2161E4946D500C2103A /* criteria */,
 				01A2D2101E4946D500C2103A /* ATDataModelv1.sqlite */,
@@ -2081,6 +2090,8 @@
 				01A2D2551E4946D600C2103A /* testCornerCasesThatShouldBeFalse.json in Resources */,
 				01A2D2531E4946D600C2103A /* testCodePointInvokesVersion.json in Resources */,
 				01A2D25F1E4946D600C2103A /* testOperatorGreaterThanOrEqual.json in Resources */,
+				018E1CE321936B6600E58F33 /* conversation-4.archive in Resources */,
+				018E1CE421936B6600E58F33 /* conversation-5.archive in Resources */,
 				01A2D25B1E4946D600C2103A /* testOperatorContains.json in Resources */,
 				01A2D24E1E4946D600C2103A /* ATDataModelv3.sqlite in Resources */,
 				01A2D26A1E4946D600C2103A /* testJsonDiffing.1.new.json in Resources */,
@@ -2280,6 +2291,7 @@
 				EFF4D2AC1EC39EC000FD4EFE /* ApptentiveAppDataContainer.m in Sources */,
 				01A2D2481E4946D600C2103A /* ApptentiveSurveyTests.m in Sources */,
 				01A2D29B1E4963A500C2103A /* ATDataModel v3 to v4.xcmappingmodel in Sources */,
+				018E1CE021936B1400E58F33 /* ApptentiveEngagementTests.swift in Sources */,
 				0174772F1EA92D7D00A0A949 /* PayloadTests.swift in Sources */,
 				01201AD31FC637BE00EB3593 /* CodePointAndInteractionTests.m in Sources */,
 				01A2D2451E4946D600C2103A /* ApptentiveMigrationTests.m in Sources */,
@@ -2382,7 +2394,7 @@
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				COPY_PHASE_STRIP = NO;
-				CURRENT_PROJECT_VERSION = 20;
+				CURRENT_PROJECT_VERSION = 23;
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
@@ -2440,7 +2452,7 @@
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				COPY_PHASE_STRIP = NO;
-				CURRENT_PROJECT_VERSION = 20;
+				CURRENT_PROJECT_VERSION = 23;
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
@@ -2472,7 +2484,7 @@
 				DEFINES_MODULE = YES;
 				DEVELOPMENT_TEAM = 86WML2UN43;
 				DYLIB_COMPATIBILITY_VERSION = 1;
-				DYLIB_CURRENT_VERSION = 20;
+				DYLIB_CURRENT_VERSION = 23;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				GCC_PREFIX_HEADER = "Apptentive/Misc/ApptentiveConnect-Prefix.pch";
 				GCC_PREPROCESSOR_DEFINITIONS = "APPTENTIVE_DEBUG=1";
@@ -2494,7 +2506,7 @@
 				DEFINES_MODULE = YES;
 				DEVELOPMENT_TEAM = 86WML2UN43;
 				DYLIB_COMPATIBILITY_VERSION = 1;
-				DYLIB_CURRENT_VERSION = 20;
+				DYLIB_CURRENT_VERSION = 23;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				GCC_PREFIX_HEADER = "Apptentive/Misc/ApptentiveConnect-Prefix.pch";
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
@@ -2538,7 +2550,6 @@
 			};
 			name = Release;
 		};
-
 /* End XCBuildConfiguration section */
 
 /* Begin XCConfigurationList section */
diff --git a/Apptentive/Apptentive/Apptentive.h b/Apptentive/Apptentive/Apptentive.h
index 24eb3390b..fe382c3ea 100644
--- a/Apptentive/Apptentive/Apptentive.h
+++ b/Apptentive/Apptentive/Apptentive.h
@@ -20,7 +20,7 @@ FOUNDATION_EXPORT double ApptentiveVersionNumber;
 FOUNDATION_EXPORT const unsigned char ApptentiveVersionString[];
 
 /** The version number of the Apptentive SDK. */
-#define kApptentiveVersionString @"5.2.2"
+#define kApptentiveVersionString @"5.2.3"
 
 /** The version number of the Apptentive API platform. */
 #define kApptentiveAPIVersionString @"9"
diff --git a/Apptentive/Apptentive/Engagement/Model/ApptentiveConversationManager.m b/Apptentive/Apptentive/Engagement/Model/ApptentiveConversationManager.m
index a9d732e4e..f7b969d44 100644
--- a/Apptentive/Apptentive/Engagement/Model/ApptentiveConversationManager.m
+++ b/Apptentive/Apptentive/Engagement/Model/ApptentiveConversationManager.m
@@ -821,6 +821,8 @@ - (BOOL)updateActiveConversation:(ApptentiveConversation *)conversation withResp
 
 		[self saveConversation:self.activeConversation];
 
+		self.messageManager.conversation = self.activeConversation;
+
 		[self handleConversationStateChange:self.activeConversation];
 
 		[self updateManifestIfNeeded];
@@ -854,10 +856,15 @@ - (BOOL)updateLegacyConversation:(ApptentiveConversation *)conversation withResp
 			mutableConversation.state = ApptentiveConversationStateAnonymous;
 		}
 
+		[self.messageManager stop];
+
 		self.activeConversation = mutableConversation;
 		self.activeConversation.delegate = self;
 
 		[self saveConversation:self.activeConversation];
+
+		self.messageManager.conversation = self.activeConversation;
+
 		[self handleConversationStateChange:self.activeConversation];
 
 		[self updateManifestIfNeeded];
diff --git a/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.h b/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.h
index accf8de60..8503d9b10 100644
--- a/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.h
+++ b/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.h
@@ -79,6 +79,18 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)invoke;
 
+
+/**
+ Adds the values from `otherCount` to the current object.
+
+ @param oldCount The older count object, presumably from a previous version.
+ @param newCount The newer count object, which would have been invoked last.
+ @return The sum of the two count objects.
+
+ @discussion If either is nil, the other one is returned. If both are nil, nil is returned.
+ */
++ (ApptentiveCount *)mergeOldCount:(nullable ApptentiveCount *)oldCount withNewCount:(nullable ApptentiveCount *)newCount;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.m b/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.m
index 60c7baa29..42f64cdf3 100644
--- a/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.m
+++ b/Apptentive/Apptentive/Engagement/Model/ApptentiveCount.m
@@ -78,6 +78,16 @@ - (NSString *)description {
 	return [NSString stringWithFormat:@"[%@] totalCount=%ld versionCount=%ld buildCount=%ld lastInvoked=%@", NSStringFromClass([self class]), (unsigned long)_totalCount, (unsigned long)_versionCount, (unsigned long)_buildCount, _lastInvoked];
 }
 
+// This is used for migrating version 5.1.0 through 5.2.2 (with unescaped code points) to 5.2.3 and later.
++ (ApptentiveCount *)mergeOldCount:(nullable ApptentiveCount *)oldCount withNewCount:(nullable ApptentiveCount *)newCount {
+	NSInteger totalCount = oldCount.totalCount + newCount.totalCount;
+	NSInteger versionCount = newCount.versionCount; // Old count is likely to be for a different version
+	NSInteger buildCount = newCount.buildCount; // Old count is likely to be for a different build
+	NSDate *lastInvoked = newCount.lastInvoked ?: oldCount.lastInvoked; // New count, if present, will have been invoked last
+
+	return [[ApptentiveCount alloc] initWithTotalCount:totalCount versionCount:versionCount buildCount:buildCount lastInvoked:lastInvoked];
+}
+
 @end
 
 
diff --git a/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.h b/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.h
index 8684b0221..814cc968e 100644
--- a/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.h
+++ b/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.h
@@ -72,6 +72,10 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)resetBuild;
 
+// Test only
++ (nullable NSString *)escapedKeyForKey:(NSString *)key;
+@property (readonly, nonatomic) NSInteger version;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.m b/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.m
index 565459908..da556b5c6 100644
--- a/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.m
+++ b/Apptentive/Apptentive/Engagement/Model/ApptentiveEngagement.m
@@ -8,11 +8,13 @@
 
 #import "ApptentiveEngagement.h"
 #import "ApptentiveCount.h"
+#import "ApptentiveBackend+Engagement.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
 static NSString *const InteractionsKey = @"interactions";
 static NSString *const CodePointsKey = @"codePoints";
+static NSString *const VersionKey = @"version";
 
 // Legacy keys
 static NSString *const ATEngagementCodePointsInvokesTotalKey = @"ATEngagementCodePointsInvokesTotalKey";
@@ -23,16 +25,16 @@
 static NSString *const ATEngagementInteractionsInvokesVersionKey = @"ATEngagementInteractionsInvokesVersionKey";
 static NSString *const ATEngagementInteractionsInvokesBuildKey = @"ATEngagementInteractionsInvokesBuildKey";
 static NSString *const ATEngagementInteractionsInvokesLastDateKey = @"ATEngagementInteractionsInvokesLastDateKey";
-
+static NSInteger const CurrentVersion = 2;
 
 @interface ApptentiveEngagement ()
 
 @property (strong, nonatomic) NSMutableDictionary<NSString *, ApptentiveCount *> *mutableInteractions;
 @property (strong, nonatomic) NSMutableDictionary<NSString *, ApptentiveCount *> *mutableCodePoints;
+@property (assign, nonatomic) NSInteger version;
 
 @end
 
-
 @implementation ApptentiveEngagement
 
 - (instancetype)init {
@@ -40,6 +42,7 @@ - (instancetype)init {
 	if (self) {
 		_mutableInteractions = [NSMutableDictionary dictionary];
 		_mutableCodePoints = [NSMutableDictionary dictionary];
+		_version = CurrentVersion;
 	}
 	return self;
 }
@@ -49,6 +52,20 @@ - (nullable instancetype)initWithCoder:(NSCoder *)coder {
 	if (self) {
 		_mutableInteractions = [coder decodeObjectOfClass:[NSMutableDictionary class] forKey:InteractionsKey];
 		_mutableCodePoints = [coder decodeObjectOfClass:[NSMutableDictionary class] forKey:CodePointsKey];
+		if ([coder containsValueForKey:VersionKey]) {
+			_version = [coder decodeIntegerForKey:VersionKey];
+		} else {
+			_version = 1;
+		}
+
+		@try {
+			if (_version != CurrentVersion) {
+				[self migrateFrom:_version to:CurrentVersion];
+			}
+		} @catch(NSException *exception) {
+			ApptentiveLogError(ApptentiveLogTagConversation, @"Caught exception %e when migrating engagement data. Starting over.", exception);
+			return [self init];
+		}
 	}
 	return self;
 }
@@ -57,8 +74,10 @@ - (void)encodeWithCoder:(NSCoder *)coder {
 	[super encodeWithCoder:coder];
 	[coder encodeObject:self.mutableInteractions forKey:InteractionsKey];
 	[coder encodeObject:self.mutableCodePoints forKey:CodePointsKey];
+	[coder encodeInteger:self.version forKey:VersionKey];
 }
 
+// This migrates pre-4.0 data stored in NSUserDefaults to 4.0 and later versions stored in NSCoding archive
 - (instancetype)initAndMigrate {
 	self = [self init];
 
@@ -96,6 +115,75 @@ + (void)deleteMigratedData {
 	[[NSUserDefaults standardUserDefaults] removeObjectForKey:ATEngagementInteractionsInvokesLastDateKey];
 }
 
+- (void)migrateFrom:(NSInteger)fromVersion to:(NSInteger)toVersion {
+	if (fromVersion == 1 && toVersion == 2) {
+		if ([self escapeUnescapedKeysInCodePoints]) {
+			_version = toVersion;
+		}
+	}
+}
+
+- (BOOL)escapeUnescapedKeysInCodePoints {
+	NSMutableArray *codePointsToMerge = [NSMutableArray array];
+
+	for (NSString *key in self.codePoints) {
+		NSString *escapedKey = [[self class] escapedKeyForKey:key];
+
+		if (escapedKey == nil) {
+			continue;
+		}
+
+		[codePointsToMerge addObject:@[key, escapedKey]];
+	}
+
+	NSMutableDictionary *escapedCodePoints = [NSMutableDictionary dictionaryWithDictionary:self.codePoints];
+	for (NSArray *keys in codePointsToMerge) {
+		NSString *key = keys[0];
+		NSString *escapedKey = keys[1];
+
+		ApptentiveCount *oldCount = [self.codePoints objectForKey:key];
+		ApptentiveCount *newCount = [self.codePoints objectForKey:escapedKey];
+		escapedCodePoints[escapedKey] = [ApptentiveCount mergeOldCount:oldCount withNewCount:newCount];
+		[escapedCodePoints removeObjectForKey:key];
+	}
+
+	_mutableCodePoints = escapedCodePoints;
+
+	return YES;
+}
+
++ (nullable NSString *)escapedKeyForKey:(NSString *)key {
+	NSArray *keyParts = [key componentsSeparatedByString:@"#"];
+
+	if (keyParts.count < 3) {
+		ApptentiveLogWarning(ApptentiveLogTagConversation, @"Unable to migrate unencoded code point %@", key);
+		return nil;
+	}
+
+	NSString *vendor = keyParts[0];
+	NSString *interaction = keyParts[1];
+	// If the event name had pound signs in it, then there will be two or more parts starting at index 2.
+	// We join those parts with a pound sign, which conveniently no-ops in the case of a single part.
+	NSString *event = [[keyParts subarrayWithRange:NSMakeRange(2, keyParts.count - 2)] componentsJoinedByString:@"#"];
+
+	if ([[self class] eventNeedsEscaping:event]) {
+		return [ApptentiveBackend codePointForVendor:vendor interactionType:interaction event:event];
+	} else {
+		return nil;
+	}
+}
+
+// Use some heuristics to see if the event name needs to be escaped and hasn't already been escaped
++ (BOOL)eventNeedsEscaping:(NSString *)event {
+	// Slashes definitey need escaping
+	BOOL slashesFound = [event containsString:@"/"];
+	// Pound signs definitely need escaping
+	BOOL poundSignsFound = [event containsString:@"#"];
+	// Third-party percent signs would also need escaping, but there aren't instances of those in our events database, so we good.
+
+	return slashesFound || poundSignsFound;
+}
+
 - (NSDictionary<NSString *, ApptentiveCount *> *)interactions {
 	return [NSDictionary dictionaryWithDictionary:self.mutableInteractions];
 }
diff --git a/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.h b/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.h
index c318667dd..69f45fefe 100644
--- a/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.h
+++ b/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.h
@@ -11,21 +11,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-extern NSString *const ATEngagementInstallDateKey;
-extern NSString *const ATEngagementUpgradeDateKey;
-extern NSString *const ATEngagementLastUsedVersionKey;
-extern NSString *const ATEngagementIsUpdateVersionKey;
-extern NSString *const ATEngagementIsUpdateBuildKey;
-extern NSString *const ATEngagementCodePointsInvokesTotalKey;
-extern NSString *const ATEngagementCodePointsInvokesVersionKey;
-extern NSString *const ATEngagementCodePointsInvokesBuildKey;
-extern NSString *const ATEngagementCodePointsInvokesLastDateKey;
-extern NSString *const ATEngagementInteractionsInvokesTotalKey;
-extern NSString *const ATEngagementInteractionsInvokesVersionKey;
-extern NSString *const ATEngagementInteractionsInvokesBuildKey;
-extern NSString *const ATEngagementInteractionsInvokesLastDateKey;
-extern NSString *const ATEngagementInteractionsSDKVersionKey;
-
 extern NSString *const ATEngagementCodePointHostAppVendorKey;
 extern NSString *const ATEngagementCodePointHostAppInteractionKey;
 extern NSString *const ATEngagementCodePointApptentiveVendorKey;
@@ -45,6 +30,7 @@ extern NSString *const ApptentiveEngagementMessageCenterEvent;
 - (BOOL)canShowInteractionForCodePoint:(NSString *)codePoint;
 
 + (NSString *)codePointForVendor:(NSString *)vendor interactionType:(NSString *)interactionType event:(NSString *)event;
++ (NSString *)stringByEscapingCodePointSeparatorCharactersInString:(NSString *)string;
 
 - (void)engageApptentiveAppEvent:(NSString *)event;
 - (void)engageLocalEvent:(NSString *)event userInfo:(nullable NSDictionary *)userInfo customData:(nullable NSDictionary *)customData extendedData:(nullable NSArray *)extendedData fromViewController:(nullable UIViewController *)viewController;
diff --git a/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.m b/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.m
index 2405a30f9..70648a0d1 100644
--- a/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.m
+++ b/Apptentive/Apptentive/Engagement/Persistence/ApptentiveBackend+Engagement.m
@@ -70,8 +70,25 @@ - (ApptentiveInteraction *)interactionForEvent:(NSString *)event {
 	return self.conversationManager.manifest.interactions[interactionIdentifier];
 }
 
++ (NSString *)stringByEscapingCodePointSeparatorCharactersInString:(NSString *)string {
+	// Only escape "%", "/", and "#".
+	// Do not change unless the server spec changes.
+	NSMutableString *escape = [string mutableCopy];
+	[escape replaceOccurrencesOfString:@"%" withString:@"%25" options:NSLiteralSearch range:NSMakeRange(0, escape.length)];
+	[escape replaceOccurrencesOfString:@"/" withString:@"%2F" options:NSLiteralSearch range:NSMakeRange(0, escape.length)];
+	[escape replaceOccurrencesOfString:@"#" withString:@"%23" options:NSLiteralSearch range:NSMakeRange(0, escape.length)];
+
+	return escape;
+}
+
 + (NSString *)codePointForVendor:(NSString *)vendor interactionType:(NSString *)interactionType event:(NSString *)event {
-	return [NSString stringWithFormat:@"%@#%@#%@", vendor, interactionType, event];;
+	NSString *encodedVendor = [[self class] stringByEscapingCodePointSeparatorCharactersInString:vendor];
+	NSString *encodedInteractionType = [[self class] stringByEscapingCodePointSeparatorCharactersInString:interactionType];
+	NSString *encodedEvent = [[self class] stringByEscapingCodePointSeparatorCharactersInString:event];
+
+	NSString *codePoint = [NSString stringWithFormat:@"%@#%@#%@", encodedVendor, encodedInteractionType, encodedEvent];
+
+	return codePoint;
 }
 
 - (void)engageApptentiveAppEvent:(NSString *)event {
diff --git a/Apptentive/Apptentive/Info.plist b/Apptentive/Apptentive/Info.plist
index 6fe1bc01a..b9a3d061c 100644
--- a/Apptentive/Apptentive/Info.plist
+++ b/Apptentive/Apptentive/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>5.2.2</string>
+	<string>5.2.3</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>NSPrincipalClass</key>
diff --git a/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.h b/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.h
index 1dc31d783..cf5e5966c 100644
--- a/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.h	
+++ b/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.h	
@@ -22,7 +22,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (readonly, nonatomic) NSString *storagePath;
 @property (readonly, nonatomic) NSString *conversationIdentifier;
 @property (readonly, nonatomic) ApptentiveDispatchQueue *operationQueue;
-@property (readonly, nonatomic) ApptentiveConversation *conversation;
+@property (strong, nonatomic) ApptentiveConversation *conversation;
 
 @property (readonly, nonatomic) ApptentiveClient *client;
 @property (assign, nonatomic) NSTimeInterval pollingInterval;
diff --git a/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.m b/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.m
index 2a1cb57f1..6d6485345 100644
--- a/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.m	
+++ b/Apptentive/Apptentive/Message Center/Model/ApptentiveMessageManager.m	
@@ -69,7 +69,7 @@ - (instancetype)initWithStoragePath:(NSString *)storagePath client:(ApptentiveCl
 
 		_didSkipProfile = [conversation.userInfo[ATMessageCenterDidSkipProfileKey] boolValue];
 		_draftMessage = conversation.userInfo[ATMessageCenterDraftMessageKey];
-		_hasSentMessage = [conversation.userInfo[ApptentiveHasSentMessageKey] boolValue];
+		_hasSentMessage = [conversation.userInfo[ApptentiveHasSentMessageKey] boolValue] || _messageStore.messages.count > 0;
 
 		for (ApptentiveMessage *message in _messageStore.messages) {
 			for (ApptentiveAttachment *attachment in message.attachments) {
diff --git a/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.h b/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.h
index b8197d506..feef6729e 100644
--- a/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.h
+++ b/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.h
@@ -40,7 +40,7 @@ typedef NS_ENUM(NSInteger, ATPendingMessageState) {
 @property (copy, nonatomic) NSString *title;
 @property (strong, nonatomic) NSOrderedSet *attachments;
 
-+ (void)enqueueUnsentMessagesInContext:(NSManagedObjectContext *)context forConversation:(ApptentiveConversation *)conversation oldAttachmentPath:(NSString *)oldAttachmentPath newAttachmentPath:(NSString *)newAttachmentPath;
++ (BOOL)enqueueUnsentMessagesInContext:(NSManagedObjectContext *)context forConversation:(ApptentiveConversation *)conversation oldAttachmentPath:(NSString *)oldAttachmentPath newAttachmentPath:(NSString *)newAttachmentPath;
 
 @end
 
diff --git a/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.m b/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.m
index 9a73f3bfc..ca920fc7d 100644
--- a/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.m
+++ b/Apptentive/Apptentive/Model/ApptentiveLegacyMessage.m
@@ -39,7 +39,7 @@ @implementation ApptentiveLegacyMessage
 @dynamic body;
 @dynamic attachments;
 
-+ (void)enqueueUnsentMessagesInContext:(NSManagedObjectContext *)context forConversation:(ApptentiveConversation *)conversation oldAttachmentPath:(NSString *)oldAttachmentPath newAttachmentPath:(NSString *)newAttachmentPath {
++ (BOOL)enqueueUnsentMessagesInContext:(NSManagedObjectContext *)context forConversation:(ApptentiveConversation *)conversation oldAttachmentPath:(NSString *)oldAttachmentPath newAttachmentPath:(NSString *)newAttachmentPath {
 	ApptentiveAssertNotNil(context, @"Context is nil");
 	ApptentiveAssertNotNil(conversation, @"Conversation is nil");
 	ApptentiveAssertNotNil(oldAttachmentPath, @"Old attachment path is nil");
@@ -53,7 +53,7 @@ + (void)enqueueUnsentMessagesInContext:(NSManagedObjectContext *)context forConv
 
 	if (unsentMessages == nil) {
 		ApptentiveLogError(ApptentiveLogTagMessages, @"Unable to retrieve unsent messages: %@", error);
-		return;
+		return NO;
 	}
 
 	for (ApptentiveLegacyMessage *legacyMessage in unsentMessages) {
@@ -108,6 +108,8 @@ + (void)enqueueUnsentMessagesInContext:(NSManagedObjectContext *)context forConv
 	if ([[NSFileManager defaultManager] fileExistsAtPath:oldAttachmentPath] && ![[NSFileManager defaultManager] removeItemAtPath:oldAttachmentPath error:&error]) {
 		ApptentiveLogWarning(ApptentiveLogTagMessages, @"Unable to remove legacy attachments directory (%@): %@", oldAttachmentPath, error);
 	}
+
+	return unsentMessages.count > 0;
 }
 
 @end
diff --git a/Apptentive/Apptentive/Persistence/ApptentiveBackend.h b/Apptentive/Apptentive/Persistence/ApptentiveBackend.h
index 0e70f5d88..f03af8030 100644
--- a/Apptentive/Apptentive/Persistence/ApptentiveBackend.h
+++ b/Apptentive/Apptentive/Persistence/ApptentiveBackend.h
@@ -19,6 +19,7 @@ extern NSString *const ApptentiveAuthenticationDidFailNotification;
 extern NSString *const ApptentiveAuthenticationDidFailNotificationKeyErrorType;
 extern NSString *const ApptentiveAuthenticationDidFailNotificationKeyErrorMessage;
 extern NSString *const ApptentiveAuthenticationDidFailNotificationKeyConversationIdentifier;
+extern NSString *const ApptentiveHasSentMessageKey;
 
 @class ApptentiveConversation, ApptentiveEngagementManifest, ApptentiveAppConfiguration, ApptentiveMessageCenterViewController, ApptentiveMessageManager, ApptentivePayloadSender, ApptentiveDispatchQueue;
 
diff --git a/Apptentive/Apptentive/Persistence/ApptentiveBackend.m b/Apptentive/Apptentive/Persistence/ApptentiveBackend.m
index a3278675e..367fef891 100644
--- a/Apptentive/Apptentive/Persistence/ApptentiveBackend.m
+++ b/Apptentive/Apptentive/Persistence/ApptentiveBackend.m
@@ -408,7 +408,8 @@ - (void)migrateLegacyCoreDataAndTaskQueueForConversation:(ApptentiveConversation
 	NSString *oldAttachmentPath = [self.supportDirectoryPath stringByAppendingPathComponent:@"attachments"];
 
 	[self.managedObjectContext performBlockAndWait:^{
-	  [ApptentiveLegacyMessage enqueueUnsentMessagesInContext:self.managedObjectContext forConversation:conversation oldAttachmentPath:oldAttachmentPath newAttachmentPath:newAttachmentPath];
+	  BOOL hasMessages = [ApptentiveLegacyMessage enqueueUnsentMessagesInContext:self.managedObjectContext forConversation:conversation oldAttachmentPath:oldAttachmentPath newAttachmentPath:newAttachmentPath];
+	  [conversation setUserInfo:@(hasMessages) forKey:ApptentiveHasSentMessageKey];
 	  [ApptentiveLegacyEvent enqueueUnsentEventsInContext:self.managedObjectContext forConversation:conversation];
 	  [ApptentiveLegacySurveyResponse enqueueUnsentSurveyResponsesInContext:self.managedObjectContext forConversation:conversation];
 
diff --git a/Apptentive/ApptentiveTests/ApptentiveEngagementTests.swift b/Apptentive/ApptentiveTests/ApptentiveEngagementTests.swift
new file mode 100644
index 000000000..14ca17afe
--- /dev/null
+++ b/Apptentive/ApptentiveTests/ApptentiveEngagementTests.swift
@@ -0,0 +1,128 @@
+//
+//  ApptentiveEngagementTests.swift
+//  ApptentiveTests
+//
+//  Created by Frank Schmitt on 11/5/18.
+//  Copyright © 2018 Apptentive, Inc. All rights reserved.
+//
+
+import XCTest
+
+class ApptentiveEngagementTests: XCTestCase {
+
+	func testEventLabelsContainingCodePointSeparatorCharacters() {
+		//Escape "%", "/", and "#".
+
+		var i = "testEventLabelSeparators";
+		var o = "testEventLabelSeparators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test#Event#Label#Separators";
+		o = "test%23Event%23Label%23Separators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test/Event/Label/Separators";
+		o = "test%2FEvent%2FLabel%2FSeparators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test%Event/Label#Separators";
+		o = "test%25Event%2FLabel%23Separators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test#Event/Label%Separators";
+		o = "test%23Event%2FLabel%25Separators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test###Event///Label%%%Separators";
+		o = "test%23%23%23Event%2F%2F%2FLabel%25%25%25Separators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test#%///#%//%%/#Event_!@#$%^&*(){}Label1234567890[]`~Separators";
+		o = "test%23%25%2F%2F%2F%23%25%2F%2F%25%25%2F%23Event_!@%23$%25^&*(){}Label1234567890[]`~Separators";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+
+		i = "test%/#";
+		o = "test%25%2F%23";
+		XCTAssertTrue(ApptentiveBackend.stringByEscapingCodePointSeparatorCharacters(in: i) == o, "Test escaping code point separator characters from event labels.");
+	}
+
+	func testMergingCounts() {
+		let aLongTimeAgo = Date(timeIntervalSinceNow: -1000)
+		let aLittleWhileAgo = Date(timeIntervalSinceNow: -500)
+
+		let oldCount = ApptentiveCount(totalCount: 5, versionCount: 10, buildCount: 20, lastInvoked: aLongTimeAgo);
+		let newCount = ApptentiveCount(totalCount: 1, versionCount: 2, buildCount: 4, lastInvoked: aLittleWhileAgo);
+
+		let mergedCount = ApptentiveCount.mergeOldCount(oldCount, withNewCount: newCount);
+
+		XCTAssertEqual(mergedCount.totalCount, 6)
+		XCTAssertEqual(mergedCount.versionCount, 2)
+		XCTAssertEqual(mergedCount.buildCount, 4)
+		XCTAssertEqual(mergedCount.lastInvoked, aLittleWhileAgo)
+
+		let mergedCount2 = ApptentiveCount.mergeOldCount(nil, withNewCount: nil)
+
+		XCTAssertEqual(mergedCount2.totalCount, 0)
+		XCTAssertEqual(mergedCount2.versionCount, 0)
+		XCTAssertEqual(mergedCount2.buildCount, 0)
+		XCTAssertEqual(mergedCount2.lastInvoked, nil)
+
+		let mergedCount3 = ApptentiveCount.mergeOldCount(oldCount, withNewCount: nil)
+
+		XCTAssertEqual(mergedCount3.totalCount, 5)
+		XCTAssertEqual(mergedCount3.versionCount, 0)
+		XCTAssertEqual(mergedCount3.buildCount, 0)
+		XCTAssertEqual(mergedCount3.lastInvoked, aLongTimeAgo)
+
+		let mergedCount4 = ApptentiveCount.mergeOldCount(nil, withNewCount: newCount)
+
+		XCTAssertEqual(mergedCount4.totalCount, 1)
+		XCTAssertEqual(mergedCount4.versionCount, 2)
+		XCTAssertEqual(mergedCount4.buildCount, 4)
+		XCTAssertEqual(mergedCount4.lastInvoked, aLittleWhileAgo)
+	}
+
+	func testEscapedKeyForKey() {
+		XCTAssertEqual(ApptentiveEngagement.escapedKey(forKey: "local#app#go/daddy"), "local#app#go%2Fdaddy")
+		XCTAssertEqual(ApptentiveEngagement.escapedKey(forKey: "local#app#go#daddy"), "local#app#go%23daddy")
+		XCTAssertEqual(ApptentiveEngagement.escapedKey(forKey: "local#app#go%25daddy"), nil)
+
+		XCTAssertEqual(ApptentiveEngagement.escapedKey(forKey: "com.apptentive#app#launch"), nil)
+	}
+
+	func testMigration() {
+		Bundle(for: ApptentiveEngagementTests.self).url(forResource: "conversation-4", withExtension:"archive")
+
+		// Open a 4.0.0 archive with slash/pound/percent event names
+		guard let fourOhUrl = Bundle(for: ApptentiveEngagementTests.self).url(forResource: "conversation-4", withExtension:"archive"), let fourOhConversation = NSKeyedUnarchiver.unarchiveObject(withFile: fourOhUrl.path) as? ApptentiveConversation else {
+			XCTFail("Can't open 4.0 conversation archive")
+			return
+		}
+
+		let fourOhEngagement = fourOhConversation.engagement
+		XCTAssertEqual(fourOhEngagement.version, 2)
+		XCTAssertEqual(fourOhEngagement.codePoints["local#app#go%2Fdaddy"]?.totalCount, 1)
+		XCTAssertEqual(fourOhEngagement.codePoints["local#app#go%2Fdaddy"]?.buildCount, 1)
+		XCTAssertEqual(fourOhEngagement.codePoints["local#app#go%2Fdaddy"]?.versionCount, 1)
+		XCTAssertEqual(fourOhEngagement.codePoints["local#app#go%23daddy"]?.totalCount, 1)
+		XCTAssertEqual(fourOhEngagement.codePoints["local#app#go%25daddy"]?.totalCount, 1)
+		XCTAssertEqual(fourOhEngagement.codePoints["local#app#go%2520daddy"]?.totalCount, 1)
+
+
+		// Open a 5.2.2 archive with slash/pound/percent event names
+		guard let fiveTwoUrl = Bundle(for: ApptentiveEngagementTests.self).url(forResource: "conversation-5", withExtension:"archive"), let fiveTwoConversation = NSKeyedUnarchiver.unarchiveObject(withFile: fiveTwoUrl.path) as? ApptentiveConversation else {
+			XCTFail("Can't open 5.2 conversation archive")
+			return
+		}
+
+		let fiveTwoEngagement = fiveTwoConversation.engagement
+		XCTAssertEqual(fiveTwoEngagement.version, 2)
+		XCTAssertEqual(fiveTwoEngagement.codePoints["local#app#go%2Fdaddy"]?.totalCount, 2)
+		XCTAssertEqual(fiveTwoEngagement.codePoints["local#app#go%2Fdaddy"]?.buildCount, 0)
+		XCTAssertEqual(fiveTwoEngagement.codePoints["local#app#go%2Fdaddy"]?.versionCount, 0)
+		XCTAssertEqual(fiveTwoEngagement.codePoints["local#app#go%23daddy"]?.totalCount, 2)
+		// No longer migrating these, as there aren't any in the wild.
+		// XCTAssertEqual(fiveTwoEngagement.codePoints["local#app#go%25daddy"]?.totalCount, 2)
+		// XCTAssertEqual(fiveTwoEngagement.codePoints["local#app#go%2520daddy"]?.totalCount, 2)
+	}
+}
diff --git a/Apptentive/ApptentiveTests/ApptentiveTests-Bridging-Header.h b/Apptentive/ApptentiveTests/ApptentiveTests-Bridging-Header.h
index 02003d140..94062678c 100644
--- a/Apptentive/ApptentiveTests/ApptentiveTests-Bridging-Header.h
+++ b/Apptentive/ApptentiveTests/ApptentiveTests-Bridging-Header.h
@@ -23,6 +23,7 @@
 #import "ApptentivePerson.h"
 #import "ApptentiveEngagement.h"
 #import "ApptentiveConversation.h"
+#import "ApptentiveCount.h"
 
 #import "ApptentiveAttachment.h"
 #import "ApptentiveMessage.h"
@@ -36,3 +37,4 @@
 #import "ApptentiveMockDispatchQueue.h"
 
 #import "ApptentiveRetryPolicy.h"
+#import "ApptentiveBackend+Engagement.h"
diff --git a/Apptentive/ApptentiveTests/Info.plist b/Apptentive/ApptentiveTests/Info.plist
index f1ef26f78..3a0895f8c 100644
--- a/Apptentive/ApptentiveTests/Info.plist
+++ b/Apptentive/ApptentiveTests/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>BNDL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>5.2.2</string>
+	<string>5.2.3</string>
 	<key>CFBundleVersion</key>
 	<string>1</string>
 </dict>
diff --git a/Apptentive/ApptentiveTests/data/conversation-4.archive b/Apptentive/ApptentiveTests/data/conversation-4.archive
new file mode 100644
index 000000000..f0d07a9e6
Binary files /dev/null and b/Apptentive/ApptentiveTests/data/conversation-4.archive differ
diff --git a/Apptentive/ApptentiveTests/data/conversation-5.archive b/Apptentive/ApptentiveTests/data/conversation-5.archive
new file mode 100644
index 000000000..67b61d8fe
Binary files /dev/null and b/Apptentive/ApptentiveTests/data/conversation-5.archive differ
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 20f6d627c..2bfab9a41 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+# 2018-11-27 - v5.2.3
+
+#### Bugs Fixed
+
+* Fix problem that required app relaunch to receive replies in Message Center.
+* Correct handling of event names that include any pound signs, percent signs, or slashes. 
+
 # 2018-10-23 - v5.2.2
 
 #### Improvements
diff --git a/Example/Podfile.lock b/Example/Podfile.lock
index 211e75db8..c43b09860 100644
--- a/Example/Podfile.lock
+++ b/Example/Podfile.lock
@@ -1,5 +1,5 @@
 PODS:
-  - apptentive-ios (5.2.2)
+  - apptentive-ios (5.2.3)
 
 DEPENDENCIES:
   - apptentive-ios (from `..`)
@@ -9,7 +9,7 @@ EXTERNAL SOURCES:
     :path: ".."
 
 SPEC CHECKSUMS:
-  apptentive-ios: 4ef3801eea4162cac3ab6aaa11448dcb26a5e42e
+  apptentive-ios: cfe3763ac1ef62af21791e57da0c30cbf28022f8
 
 PODFILE CHECKSUM: 89d2b5f4683b04482e89df6d46b268cc9ed1ef79
 
diff --git a/apptentive-ios.podspec b/apptentive-ios.podspec
index 2739d67ab..8b42ecebc 100644
--- a/apptentive-ios.podspec
+++ b/apptentive-ios.podspec
@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.name     = 'apptentive-ios'
   s.module_name = 'Apptentive'
-  s.version  = '5.2.2'
+  s.version  = '5.2.3'
   s.license  = 'BSD'
   s.summary  = 'Apptentive Customer Communications SDK.'
   s.homepage = 'https://www.apptentive.com/'