-

diff --git a/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/DUOSkill.swift b/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/DUOSkill.swift
index f8d3c1fa6..e047ffdad 100644
--- a/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/DUOSkill.swift
+++ b/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/DUOSkill.swift
@@ -8,139 +8,140 @@
 
 import Foundation
 
-final class DUOSkill: NSObject, DUOCoding {
-
-    /// Present and true iff user can open this skill.
-    let isAccessible: Bool
-
-    /// Present and true iff this is a bonus skill.
-    let isBonusSkill: Bool
-
-    /// Tips and notes.
-    let explanation: String?
-
-    /// Number of lessons completed by the user.
-    let finishedLessons: Int
-
-    /// Number of levels completed by the user.
-    let finishedLevels: Int
-
-    /// From language.
-    let fromLanguage: Language
-
-    /// Icon ID. The icon's image and color are bundled with the client.
-    let iconId: Int
-
-    /// Skill ID.
-    let id: String
-
-    /// Learning language.
-    let learningLanguage: Language
-
-    /// Array of words taught per lesson.
-    let lessonWords: [String]
-
-    /// Number of lessons in this skill.
-    let lessons: Int
-
-    /// Number of levels in this skill.
-    let levels: Int
-
-    /// Skill name as shown on the skill page.
-    let name: String
-
-    /// Skill name as shown in the skill tree.
-    let shortName: String
-
-    /// Skill strength as a float.
-    let strength: Double
-
-    /// Skill name as shown in web's skill page URL.
-    let urlName: String?
-
-    /// Weakest words.
-    let weakWords: [String]
-
-    init(isAccessible: Bool,
-         isBonusSkill: Bool,
-         explanation: String?,
-         finishedLessons: Int,
-         finishedLevels: Int,
-         fromLanguage: Language,
-         iconId: Int,
-         id: String,
-         learningLanguage: Language,
-         lessonWords: [String],
-         lessons: Int,
-         levels: Int,
-         name: String,
-         shortName: String,
-         strength: Double,
-         urlName: String?,
-         weakWords: [String]) {
-        self.isAccessible = isAccessible
-        self.isBonusSkill = isBonusSkill
-        self.explanation = explanation
-        self.finishedLessons = finishedLessons
-        self.finishedLevels = finishedLevels
-        self.fromLanguage = fromLanguage
-        self.iconId = iconId
-        self.id = id
-        self.learningLanguage = learningLanguage
-        self.lessonWords = lessonWords
-        self.lessons = lessons
-        self.levels = levels
-        self.name = name
-        self.shortName = shortName
-        self.strength = strength
-        self.urlName = urlName
-        self.weakWords = weakWords
-    }
-
-    func encode(with aCoder: NSCoder) {
-        duoEncoded().forEach { key, value in
-            aCoder.encode(value, forKey: key)
-        }
-    }
-
-    convenience init?(coder aDecoder: NSCoder) {
-        self.init(subscriptable: aDecoder)
-    }
-
-    convenience init?<T: Subscriptable>(subscriptable sub: T) where T.Key == String, T.Value == NSObject {
-        guard
-            let accessible = sub["accessible"] as? Bool,
-            let bonus = sub["bonus"] as? Bool,
-            let iconId = sub["iconId"] as? Int,
-            let id = sub["id"] as? String,
-            let fromLanguageID = sub["fromLanguage"] as? String,
-            let learningLanguageID = sub["learningLanguage"] as? String,
-            let lessonWords = sub["lessonWords"] as? [String],
-            let lessons = sub["lessons"] as? Int,
-            let name = sub["name"] as? String,
-            let shortName = sub["shortName"] as? String,
-            let weakWords = sub["weakWords"] as? [String]
-        else {
-            return nil
-        }
-
-        self.init(isAccessible: accessible,
-                  isBonusSkill: bonus,
-                  explanation: sub["explanation"] as? String,
-                  finishedLessons: (sub["finishedLessons"] as? Int) ?? 0,
-                  finishedLevels: (sub["finishedLevels"] as? Int) ?? 0,
-                  fromLanguage: Language(id: fromLanguageID),
-                  iconId: iconId,
-                  id: id,
-                  learningLanguage: Language(id: learningLanguageID),
-                  lessonWords: lessonWords,
-                  lessons: lessons,
-                  levels: (sub["levels"] as? Int) ?? 0,
-                  name: name,
-                  shortName: shortName,
-                  strength: (sub["strength"] as? Double) ?? 0,
-                  urlName: sub["urlName"] as? String,
-                  weakWords: weakWords)
-    }
+//final class DUOSkill: NSObject, DUOCoding {
+//
+//    /// Present and true iff user can open this skill.
+//    let isAccessible: Bool
+//
+//    /// Present and true iff this is a bonus skill.
+//    let isBonusSkill: Bool
+//
+//    /// Tips and notes.
+////    let explanation: String?
+//
+//    /// Number of lessons completed by the user.
+//    let finishedLessons: Int
+//
+//    /// Number of levels completed by the user.
+//    let finishedLevels: Int
+//
+//    /// From language.
+//    let fromLanguage: Language
+//
+//    /// Icon ID. The icon's image and color are bundled with the client.
+//    let iconId: Int
+//
+//    /// Skill ID.
+//    let id: String
+//
+//    /// Learning language.
+//    let learningLanguage: Language
+//
+//    /// Array of words taught per lesson.
+//    let lessonWords: [String]
+//
+//    /// Number of lessons in this skill.
+//    let lessons: Int
+//
+//    /// Number of levels in this skill.
+//    let levels: Int
+//
+//    /// Skill name as shown on the skill page.
+//    let name: String
+//
+//    /// Skill name as shown in the skill tree.
+//    let shortName: String
+//
+//    /// Skill strength as a float.
+//    let strength: Double
+//
+//    /// Skill name as shown in web's skill page URL.
+//    let urlName: String?
+//
+//    /// Weakest words.
+//    let weakWords: [String]
+//
+//    init(isAccessible: Bool,
+//         isBonusSkill: Bool,
+//         explanation: String?,
+//         finishedLessons: Int,
+//         finishedLevels: Int,
+//         fromLanguage: Language,
+//         iconId: Int,
+//         id: String,
+//         learningLanguage: Language,
+//         lessonWords: [String],
+//         lessons: Int,
+//         levels: Int,
+//         name: String,
+//         shortName: String,
+//         strength: Double,
+//         urlName: String?,
+//         weakWords: [String]) {
+//        self.isAccessible = isAccessible
+//        self.isBonusSkill = isBonusSkill
+////        self.explanation = explanation
+//        self.finishedLessons = finishedLessons
+//        self.finishedLevels = finishedLevels
+//        self.fromLanguage = fromLanguage
+//        self.iconId = iconId
+//        self.id = id
+//        self.learningLanguage = learningLanguage
+//        self.lessonWords = lessonWords
+//        self.lessons = lessons
+//        self.levels = levels
+//        self.name = name
+//        self.shortName = shortName
+//        self.strength = strength
+//        self.urlName = urlName
+//        self.weakWords = weakWords
+//    }
+//
+//    func encode(with aCoder: NSCoder) {
+//        duoEncoded().forEach { key, value in
+//            aCoder.encode(value, forKey: key)
+//        }
+//    }
+//
+//    convenience init?(coder aDecoder: NSCoder) {
+//        self.init(subscriptable: aDecoder)
+//    }
+//
+//    convenience init?<T: Subscriptable>(subscriptable sub: T) where T.Key == String, T.Value == NSObject {
+//        guard
+//            let accessible = sub["accessible"] as? Bool,
+//            let bonus = sub["bonus"] as? Bool,
+//            let iconId = sub["iconId"] as? Int,
+//            let id = sub["id"] as? String,
+//            let fromLanguageID = sub["fromLanguage"] as? String,
+//            let learningLanguageID = sub["learningLanguage"] as? String,
+//            let lessonWords = sub["lessonWords"] as? [String],
+//            let lessons = sub["lessons"] as? Int,
+//            let name = sub["name"] as? String,
+//            let shortName = sub["shortName"] as? String,
+//            let weakWords = sub["weakWords"] as? [String]
+//        else {
+//            return nil
+//        }
+//
+//        self.init(isAccessible: accessible,
+//                  isBonusSkill: bonus,
+//                  explanation: sub["explanation"] as? String,
+//                  finishedLessons: (sub["finishedLessons"] as? Int) ?? 0,
+//                  finishedLevels: (sub["finishedLevels"] as? Int) ?? 0,
+//                  fromLanguage: Language(id: fromLanguageID),
+//                  iconId: iconId,
+//                  id: id,
+//                  learningLanguage: Language(id: learningLanguageID),
+//                  lessonWords: lessonWords,
+//                  lessons: lessons,
+//                  levels: (sub["levels"] as? Int) ?? 0,
+//                  name: name,
+//                  shortName: shortName,
+//                  strength: (sub["strength"] as? Double) ?? 0,
+//                  urlName: sub["urlName"] as? String,
+//                  weakWords: weakWords)
+//    }
+//
+//}
 
-}
diff --git a/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/Extensions/DUOSkill+Extensions.swift b/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/Extensions/DUOSkill+Extensions.swift
index 36a2e631e..37f0cd814 100644
--- a/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/Extensions/DUOSkill+Extensions.swift
+++ b/DuolingoMobile/Sources/Library/Networking/NetworkClient/Models/Extensions/DUOSkill+Extensions.swift
@@ -8,29 +8,75 @@
 
 import Foundation
 
-extension DUOSkill {
-
-    /// The color to use for the skill when it is locked.
-    static var lockedColor: UIColor {
-        return UIColor.duolingoNewVeryLightGray()
-    }
-
-    /// The color to use for the skill when it is at full strength, i.e. gold.
-    static var goldColor: UIColor {
-        return UIColor.duolingoNewGold()
-    }
+//extension DUOSkill {
+//
+//    /// The color to use for the skill when it is locked.
+//    static var lockedColor: UIColor {
+//        return UIColor.duolingoNewVeryLightGray()
+//    }
+//
+//    /// The color to use for the skill when it is at full strength, i.e. gold.
+//    static var goldColor: UIColor {
+//        return UIColor.duolingoNewGold()
+//    }
+//
+//    /// The color to use for the skill when it is unlocked, but not gilded.
+//    static func unlockedColor(iconID: Int) -> UIColor {
+//        let graphics = DUOGraphicsManager.instance()
+//        guard
+//            let colorType = graphics?.colorType(forIconID: iconID),
+//            let color = graphics?.color(for: colorType)
+//        else {
+//                return UIColor.duolingoRed()
+//        }
+//
+//        return color
+//    }
+//
+//    /// The strength that a skill has to be above in order for it to be considered gold.
+//    @objc static var goldStrength: Double {
+//        return 0.75
+//    }
+//
+//    /// Whether the skill's strength is high enough to be considered full strength.
+//    @objc static func isFullStrength(_ strength: Double) -> Bool {
+//        if StrengthBarExperiment.condition.isControl {
+//            return strength > goldStrength
+//        } else {
+//            return strength >= goldStrength
+//        }
+//    }
+//
+//    /// Whether or not the skill should be considered gold.
+//    var isGilded: Bool {
+//        return finishedLessons >= lessons && DUOSkill.isFullStrength(strength)
+//    }
+//
+//    /// The current color for this skill, based on the current status.
+//    var iconColor: UIColor {
+//        if !self.isAccessible {
+//            return DUOSkill.lockedColor
+//        } else if isGilded {
+//            return DUOSkill.goldColor
+//        } else {
+//            return DUOSkill.unlockedColor(iconID: iconId)
+//        }
+//    }
+//
+//    /// Returns a newly-loaded image for this icon.
+//    func loadIconImage() -> PDFImage {
+//        return DUOGraphicsManager.instance().icon(forIconIndex: iconId,
+//                                                  locked: !isAccessible,
+//                                                  fullStrength: isGilded)
+//    }
+//
+//}
 
-    /// The color to use for the skill when it is unlocked, but not gilded.
-    static func unlockedColor(iconID: Int) -> UIColor {
-        let graphics = DUOGraphicsManager.instance()
-        guard
-            let colorType = graphics?.colorType(forIconID: iconID),
-            let color = graphics?.color(for: colorType)
-        else {
-                return UIColor.duolingoRed()
-        }
+extension DUOSkillSummary {
 
-        return color
+    /// Whether or not the user has completed the skill.
+    var isCompleted: Bool {
+        return finishedLessons >= lessons
     }
 
     /// The strength that a skill has to be above in order for it to be considered gold.
@@ -47,51 +93,42 @@ extension DUOSkill {
         }
     }
 
-    /// Whether or not the skill should be considered gold.
-    var isGilded: Bool {
-        return finishedLessons >= lessons && DUOSkill.isFullStrength(strength)
-    }
-
-    /// The current color for this skill, based on the current status.
-    var iconColor: UIColor {
-        if !self.isAccessible {
-            return DUOSkill.lockedColor
-        } else if isGilded {
-            return DUOSkill.goldColor
-        } else {
-            return DUOSkill.unlockedColor(iconID: iconId)
-        }
+    /// The color to use for the skill when it is locked.
+    private static var lockedColor: UIColor {
+        return UIColor.duolingoNewVeryLightGray()
     }
 
-    /// Returns a newly-loaded image for this icon.
-    func loadIconImage() -> PDFImage {
-        return DUOGraphicsManager.instance().icon(forIconIndex: iconId,
-                                                  locked: !isAccessible,
-                                                  fullStrength: isGilded)
+    /// The color to use for the skill when it is at full strength, i.e. gold.
+    private static var goldColor: UIColor {
+        return UIColor.duolingoNewGold()
     }
 
-}
-
-extension DUOSkillSummary {
+    /// The color to use for the skill when it is unlocked, but not gilded.
+    private static func unlockedColor(iconID: Int) -> UIColor {
+        let graphics = DUOGraphicsManager.instance()
+        guard
+            let colorType = graphics?.colorType(forIconID: iconID),
+            let color = graphics?.color(for: colorType)
+        else {
+                return UIColor.duolingoRed()
+        }
 
-    /// Whether or not the user has completed the skill.
-    var isCompleted: Bool {
-        return finishedLessons >= lessons
+        return color
     }
 
     /// Whether or not the skill should be considered gold.
     var isGilded: Bool {
-        return isCompleted && DUOSkill.isFullStrength(strength)
+        return isCompleted && DUOSkillSummary.isFullStrength(strength)
     }
 
     /// The current color for this skill, based on the current status.
     var iconColor: UIColor {
         if !self.isAccessible {
-            return DUOSkill.lockedColor
+            return DUOSkillSummary.lockedColor
         } else if isGilded {
-            return DUOSkill.goldColor
+            return DUOSkillSummary.goldColor
         } else {
-            return DUOSkill.unlockedColor(iconID: iconId)
+            return DUOSkillSummary.unlockedColor(iconID: iconId)
         }
     }
 
diff --git a/DuolingoMobile/Sources/Library/Networking/NetworkClient/Serializers/DUOSkillSerializer.swift b/DuolingoMobile/Sources/Library/Networking/NetworkClient/Serializers/DUOSkillSerializer.swift
index 54ca65dbb..da5aaeb8f 100644
--- a/DuolingoMobile/Sources/Library/Networking/NetworkClient/Serializers/DUOSkillSerializer.swift
+++ b/DuolingoMobile/Sources/Library/Networking/NetworkClient/Serializers/DUOSkillSerializer.swift
@@ -8,32 +8,33 @@
 
 import Foundation
 
-extension DUOSkill {
-    func duoEncoded() -> [String: NSObject] {
-        return DUOSkillSerializer.jsonFromSkill(self)
-    }
-}
+//extension DUOSkill {
+//    func duoEncoded() -> [String: NSObject] {
+//        return DUOSkillSerializer.jsonFromSkill(self)
+//    }
+//}
+//
+//class DUOSkillSerializer: NSObject {
+//    class func jsonFromSkill(_ skill: DUOSkill) -> JSONObject {
+//        var json = JSONObject()
+//        json["accessible"] = skill.isAccessible as NSNumber
+//        json["bonus"] = skill.isBonusSkill as NSNumber
+////        json["explanation"] = skill.explanation as NSString?
+//        json["finishedLessons"] = skill.finishedLessons as NSNumber
+//        json["finishedLevels"] = skill.finishedLevels as NSNumber
+//        json["fromLanguage"] = skill.fromLanguage.id as NSString
+//        json["iconId"] = skill.iconId as NSNumber
+//        json["id"] = skill.id as NSString
+//        json["learningLanguage"] = skill.learningLanguage.id as NSString
+//        json["lessonWords"] = skill.lessonWords as NSArray
+//        json["lessons"] = skill.lessons as NSNumber
+//        json["levels"] = skill.levels as NSNumber
+//        json["name"] = skill.name as NSString?
+//        json["shortName"] = skill.shortName as NSString
+//        json["strength"] = skill.strength as NSNumber
+//        json["urlName"] = skill.urlName as NSString?
+//        json["weakWords"] = skill.weakWords as NSArray
+//        return json
+//    }
+//}
 
-class DUOSkillSerializer: NSObject {
-    class func jsonFromSkill(_ skill: DUOSkill) -> JSONObject {
-        var json = JSONObject()
-        json["accessible"] = skill.isAccessible as NSNumber
-        json["bonus"] = skill.isBonusSkill as NSNumber
-        json["explanation"] = skill.explanation as NSString?
-        json["finishedLessons"] = skill.finishedLessons as NSNumber
-        json["finishedLevels"] = skill.finishedLevels as NSNumber
-        json["fromLanguage"] = skill.fromLanguage.id as NSString
-        json["iconId"] = skill.iconId as NSNumber
-        json["id"] = skill.id as NSString
-        json["learningLanguage"] = skill.learningLanguage.id as NSString
-        json["lessonWords"] = skill.lessonWords as NSArray
-        json["lessons"] = skill.lessons as NSNumber
-        json["levels"] = skill.levels as NSNumber
-        json["name"] = skill.name as NSString?
-        json["shortName"] = skill.shortName as NSString
-        json["strength"] = skill.strength as NSNumber
-        json["urlName"] = skill.urlName as NSString?
-        json["weakWords"] = skill.weakWords as NSArray
-        return json
-    }
-}
diff --git a/DuolingoMobile/Sources/Library/UI/Views/StrengthBarView.swift b/DuolingoMobile/Sources/Library/UI/Views/StrengthBarView.swift
index 244862bc4..bc4cf80d1 100644
--- a/DuolingoMobile/Sources/Library/UI/Views/StrengthBarView.swift
+++ b/DuolingoMobile/Sources/Library/UI/Views/StrengthBarView.swift
@@ -456,10 +456,10 @@ private struct ContinuousStrengthBar: StrengthBarDrawable {
     func percentFilled(strength: Double) -> Double {
         if strength <= 0 {
             return 0
-        } else if strength > DUOSkill.goldStrength {
+        } else if strength > DUOSkillSummary.goldStrength {
             return 1
         } else {
-            return strength / DUOSkill.goldStrength
+            return strength / DUOSkillSummary.goldStrength
         }
     }
 
diff --git a/DuolingoMobile/Sources/Sessions/Controllers/Session End/DUOSessionCompleteController.m b/DuolingoMobile/Sources/Sessions/Controllers/Session End/DUOSessionCompleteController.m
index e478415f9..d89e3eef0 100644
--- a/DuolingoMobile/Sources/Sessions/Controllers/Session End/DUOSessionCompleteController.m	
+++ b/DuolingoMobile/Sources/Sessions/Controllers/Session End/DUOSessionCompleteController.m	
@@ -700,7 +700,7 @@ - (void)populateAwardViewControllers
 
             UIViewController<DUOFlowAnimatable> *awardVC;
             if (DUOStrengthBarExperiment.condition.useNewStrengthenedSkillVC) {
-                double goldStrength = DUOSkill.goldStrength;
+                double goldStrength = DUOSkillSummary.goldStrength;
                 double emptyStrength = goldStrength * 0.1;
                 NSInteger maxSkills = 3;
                 NSInteger numberOfSkills = MIN(maxSkills, self.model.learnedSkills.count);
diff --git a/DuolingoMobile/Sources/Sessions/Controllers/Session End/StrengthenedSkillAwardVC.swift b/DuolingoMobile/Sources/Sessions/Controllers/Session End/StrengthenedSkillAwardVC.swift
index 127654c37..4e0a2a441 100644
--- a/DuolingoMobile/Sources/Sessions/Controllers/Session End/StrengthenedSkillAwardVC.swift	
+++ b/DuolingoMobile/Sources/Sessions/Controllers/Session End/StrengthenedSkillAwardVC.swift	
@@ -198,7 +198,7 @@ private func modifyIncreaseForAnimation(_ increase: SkillIncreaseModel) -> Skill
     var before = Double(increase.strengthBefore)
     var after = Double(increase.strengthAfter)
 
-    let goldStrength = DUOSkill.goldStrength
+    let goldStrength = DUOSkillSummary.goldStrength
     var beforePercent = before / goldStrength
     var afterPercent = after / goldStrength
 
diff --git a/DuolingoMobile/Sources/Skills/Skill Tree/Views/DUOSkillTreeItem.m b/DuolingoMobile/Sources/Skills/Skill Tree/Views/DUOSkillTreeItem.m
index 80477019b..96df93d0b 100644
--- a/DuolingoMobile/Sources/Skills/Skill Tree/Views/DUOSkillTreeItem.m	
+++ b/DuolingoMobile/Sources/Skills/Skill Tree/Views/DUOSkillTreeItem.m	
@@ -162,7 +162,7 @@ - (void)setItemModel:(DUOSkillTreeItemModel *)itemModel
     self.badgeView.hidden = (itemModel.skill.missingLessons == 0 || itemModel.skill.isLocked)
                             || !DUOStrengthBarExperiment.condition.showsNotification;
 
-    BOOL fullStrength = itemModel.skill.isLearned && [DUOSkill isFullStrength:itemModel.skill.strength];
+    BOOL fullStrength = itemModel.skill.isLearned && [DUOSkillSummary isFullStrength:itemModel.skill.strength];
 
     if (![previousItemModel.skill.name isEqualToString:itemModel.skill.name] || self.skillWasLocked != itemModel.skill.isLocked || self.skillWasLearned != itemModel.skill.isLearned || self.skillWasFullStrength != fullStrength) {
         NSInteger requestedIndex = itemModel.skill.iconIndex;
diff --git a/DuolingoMobile/Sources/Skills/Skill View/Controllers/DUOSkillViewController.m b/DuolingoMobile/Sources/Skills/Skill View/Controllers/DUOSkillViewController.m
index 9ff26f557..d2c824721 100644
--- a/DuolingoMobile/Sources/Skills/Skill View/Controllers/DUOSkillViewController.m	
+++ b/DuolingoMobile/Sources/Skills/Skill View/Controllers/DUOSkillViewController.m	
@@ -498,7 +498,7 @@ - (void)updateStrength
         finishedWithLessons = finishedWithLessons && pathItemComplete;
     }
 
-    BOOL fullStrength = finishedWithLessons && [DUOSkill isFullStrength:self.skill.strength];
+    BOOL fullStrength = finishedWithLessons && [DUOSkillSummary isFullStrength:self.skill.strength];
     self.icon.image = [[DUOGraphicsManager instance] iconForIconIndex:self.skill.iconIndex locked:self.skill.isLocked fullStrength:fullStrength];
     self.skillColor = [[DUOGraphicsManager instance] paletteColorForIconColorType:self.skill.iconColorType locked:self.skill.isLocked fullStrength:fullStrength shiny:fullStrength];
     self.backgroundShape.image = [[DUOGraphicsManager instance] ellipseForIconColorType:self.skill.iconColorType locked:self.skill.isLocked fullStrength:fullStrength shiny:fullStrength];