Aggressively nag iOS 8 users to upgrade iOS.

Signal/src/ViewControllers/HomeViewController.m

@@ -560,6 +560,8 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
                          }];
     } else if (!self.hasBeenPresented && [ProfileViewController shouldDisplayProfileViewOnLaunch]) {
         [ProfileViewController presentForUpgradeOrNag:self];
+    } else {
+        [OWSAlerts showIOSUpgradeNagIfNecessary];
     }
 
     self.hasBeenPresented = YES;

Signal/src/ViewControllers/NewContactThreadViewController.m

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 #import "NewContactThreadViewController.h"
@@ -278,35 +278,7 @@ NS_ASSUME_NONNULL_BEGIN
 {
     [super viewDidAppear:animated];
 
-    [self showIOSUpgradeNagIfNecessary];
-}
-
-- (void)showIOSUpgradeNagIfNecessary
-{
-    // Only show the nag to iOS 8 users.
-    if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(9, 0)) {
-        return;
-    }
-
-    // Don't show the nag to users who have just launched
-    // the app for the first time.
-    if (![AppVersion instance].lastAppVersion) {
-        return;
-    }
-
-    // Only show the nag once per update of the app.
-    NSString *currentAppVersion = [AppVersion instance].currentAppVersion;
-    OWSAssert(currentAppVersion.length > 0);
-    NSString *lastNagAppVersion = [Environment.preferences iOSUpgradeNagVersion];
-    if (lastNagAppVersion && ![lastNagAppVersion isEqualToString:currentAppVersion]) {
-
-        [Environment.preferences setIOSUpgradeNagVersion:currentAppVersion];
-
-        [OWSAlerts showAlertWithTitle:NSLocalizedString(@"UPGRADE_IOS_ALERT_TITLE",
-                                          @"Title for the alert indicating that user should upgrade iOS.")
-                              message:NSLocalizedString(@"UPGRADE_IOS_ALERT_MESSAGE",
-                                          @"Message for the alert indicating that user should upgrade iOS.")];
-    }
+    [OWSAlerts showIOSUpgradeNagIfNecessary];
 }
 
 #pragma mark - Table Contents

Signal/translations/en.lproj/Localizable.strings

@@ -1789,7 +1789,7 @@
 "UPGRADE_EXPERIENCE_VIDEO_TITLE" = "Hello Secure Video Calls!";
 
 /* Message for the alert indicating that user should upgrade iOS. */
-"UPGRADE_IOS_ALERT_MESSAGE" = "Signal will soon require iOS 9 or later. Please upgrade in Settings app >> General >> Software Update.";
+"UPGRADE_IOS_ALERT_MESSAGE" = "Signal requires iOS 9 or later. Please upgrade iOS in Settings app >> General >> Software Update.";
 
 /* Title for the alert indicating that user should upgrade iOS. */
 "UPGRADE_IOS_ALERT_TITLE" = "Upgrade iOS";

SignalMessaging/utils/OWSPreferences.h

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 NS_ASSUME_NONNULL_BEGIN
@@ -58,8 +58,8 @@ extern NSString *const OWSPreferencesKeyEnableDebugLog;
 - (BOOL)hasDeclinedNoContactsView;
 - (void)setHasDeclinedNoContactsView:(BOOL)value;
 
-- (void)setIOSUpgradeNagVersion:(NSString *)value;
-- (nullable NSString *)iOSUpgradeNagVersion;
+- (void)setIOSUpgradeNagDate:(NSDate *)value;
+- (nullable NSDate *)iOSUpgradeNagDate;
 
 #pragma mark - Calling
 

SignalMessaging/utils/OWSPreferences.m

@@ -24,7 +24,7 @@ NSString *const OWSPreferencesKeyCallKitEnabled = @"CallKitEnabled";
 NSString *const OWSPreferencesKeyCallKitPrivacyEnabled = @"CallKitPrivacyEnabled";
 NSString *const OWSPreferencesKeyCallsHideIPAddress = @"CallsHideIPAddress";
 NSString *const OWSPreferencesKeyHasDeclinedNoContactsView = @"hasDeclinedNoContactsView";
-NSString *const OWSPreferencesKeyIOSUpgradeNagVersion = @"iOSUpgradeNagVersion";
+NSString *const OWSPreferencesKeyIOSUpgradeNagDate = @"iOSUpgradeNagDate";
 NSString *const OWSPreferencesKey_IsReadyForAppExtensions = @"isReadyForAppExtensions_5";
 NSString *const OWSPreferencesKey_IsRegistered = @"OWSPreferencesKey_IsRegistered";
 
@@ -179,14 +179,14 @@ NSString *const OWSPreferencesKey_IsRegistered = @"OWSPreferencesKey_IsRegistere
     [self setValueForKey:OWSPreferencesKeyHasDeclinedNoContactsView toValue:@(value)];
 }
 
-- (void)setIOSUpgradeNagVersion:(NSString *)value
+- (void)setIOSUpgradeNagDate:(NSDate *)value
 {
-    [self setValueForKey:OWSPreferencesKeyIOSUpgradeNagVersion toValue:value];
+    [self setValueForKey:OWSPreferencesKeyIOSUpgradeNagDate toValue:value];
 }
 
-- (nullable NSString *)iOSUpgradeNagVersion
+- (nullable NSDate *)iOSUpgradeNagDate
 {
-    return [self tryGetValueForKey:OWSPreferencesKeyIOSUpgradeNagVersion];
+    return [self tryGetValueForKey:OWSPreferencesKeyIOSUpgradeNagDate];
 }
 
 #pragma mark - Calling

SignalMessaging/views/OWSAlerts.swift

@@ -65,4 +65,32 @@ import Foundation
         return action
     }
 
+    @objc
+    public class func showIOSUpgradeNagIfNecessary() {
+        // Only show the nag to iOS 8 users.
+        if #available(iOS 9.0, *) {
+            return
+        }
+
+        // Don't show the nag to users who have just launched
+        // the app for the first time.
+        guard let _ = AppVersion.instance().lastAppVersion else {
+            return
+        }
+
+        if let iOSUpgradeNagDate = Environment.preferences().iOSUpgradeNagDate() {
+            // Nag no more than once every three days.
+            let kNagFrequencySeconds = 3 * kDayInterval
+            guard fabs(iOSUpgradeNagDate.timeIntervalSinceNow) > kNagFrequencySeconds else {
+                return
+            }
+        }
+
+        Environment.preferences().setIOSUpgradeNagDate(Date())
+
+        OWSAlerts.showAlert(withTitle:NSLocalizedString("UPGRADE_IOS_ALERT_TITLE",
+                                                        comment:"Title for the alert indicating that user should upgrade iOS."),
+                            message:NSLocalizedString("UPGRADE_IOS_ALERT_MESSAGE",
+                                                      comment:"Message for the alert indicating that user should upgrade iOS."))
+    }
 }

SignalServiceKit/src/Account/TSPreKeyManager.m

@@ -15,17 +15,17 @@
 // Time before deletion of signed prekeys (measured in seconds)
 //
 // Currently we retain signed prekeys for at least 7 days.
-static const NSTimeInterval kSignedPreKeysDeletionTime = 7 * kDayInterval;
+#define kSignedPreKeysDeletionTime ((NSTimeInterval)7 * kDayInterval)
 
 // Time before rotation of signed prekeys (measured in seconds)
 //
 // Currently we rotate signed prekeys every 2 days (48 hours).
-static const NSTimeInterval kSignedPreKeyRotationTime = 2 * kDayInterval;
+#define kSignedPreKeyRotationTime ((NSTimeInterval)7 * kDayInterval)
 
 // How often we check prekey state on app activation.
 //
 // Currently we check prekey state every 12 hours.
-static const NSTimeInterval kPreKeyCheckFrequencySeconds = 12 * kHourInterval;
+#define kPreKeyCheckFrequencySeconds ((NSTimeInterval)12 * kHourInterval)
 
 // We generate 100 one-time prekeys at a time.  We should replenish
 // whenever ~2/3 of them have been consumed.
@@ -42,7 +42,7 @@ static const NSUInteger kMaxPrekeyUpdateFailureCount = 5;
 // before the message sending is disabled.
 //
 // Current value is 10 days (240 hours).
-static const NSTimeInterval kSignedPreKeyUpdateFailureMaxFailureDuration = 10 * kDayInterval;
+#define kSignedPreKeyUpdateFailureMaxFailureDuration ((NSTimeInterval)10 * kDayInterval)
 
 #pragma mark -
 

SignalServiceKit/src/Contacts/OWSDisappearingMessagesConfiguration.h

@@ -6,7 +6,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-extern const uint32_t OWSDisappearingMessagesConfigurationDefaultExpirationDuration;
+#define OWSDisappearingMessagesConfigurationDefaultExpirationDuration kDayInterval
 
 @interface OWSDisappearingMessagesConfiguration : TSYapDatabaseObject
 

SignalServiceKit/src/Contacts/OWSDisappearingMessagesConfiguration.m

@@ -7,9 +7,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-// 1 day.
-const uint32_t OWSDisappearingMessagesConfigurationDefaultExpirationDuration = kDayInterval;
-
 @interface OWSDisappearingMessagesConfiguration ()
 
 // Transient record lifecycle attributes.

SignalServiceKit/src/Util/NSDate+OWS.h

@@ -5,11 +5,11 @@
 NS_ASSUME_NONNULL_BEGIN
 
 // These NSTimeInterval constants provide simplified durations for readability.
-#define kMinuteInterval 60
-#define kHourInterval (60 * kMinuteInterval)
-#define kDayInterval (24 * kHourInterval)
-#define kWeekInterval (7 * kDayInterval)
-#define kMonthInterval (30 * kDayInterval)
+extern const NSTimeInterval kMinuteInterval;
+extern const NSTimeInterval kHourInterval;
+extern const NSTimeInterval kDayInterval;
+extern const NSTimeInterval kWeekInterval;
+extern const NSTimeInterval kMonthInterval;
 
 #define kSecondInMs 1000
 #define kMinuteInMs (kSecondInMs * 60)

SignalServiceKit/src/Util/NSDate+OWS.mm

@@ -7,6 +7,12 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+const NSTimeInterval kMinuteInterval = 60;
+const NSTimeInterval kHourInterval = 60 * kMinuteInterval;
+const NSTimeInterval kDayInterval = 24 * kHourInterval;
+const NSTimeInterval kWeekInterval = 7 * kDayInterval;
+const NSTimeInterval kMonthInterval = 30 * kDayInterval;
+
 @implementation NSDate (OWS)
 
 + (uint64_t)ows_millisecondTimeStamp