diff --git a/src/main/java/world/bentobox/challenges/ChallengesManager.java b/src/main/java/world/bentobox/challenges/ChallengesManager.java
index 9a7c54f..f8bca18 100644
--- a/src/main/java/world/bentobox/challenges/ChallengesManager.java
+++ b/src/main/java/world/bentobox/challenges/ChallengesManager.java
@@ -112,6 +112,77 @@ public class ChallengesManager
         this.playerCacheData = new HashMap<>();
 
         this.load();
+
+        // TODO: Remove this code after some time, as this is just a protective code against invalid world names.
+        if (Bukkit.getBukkitVersion().startsWith("1.14"))
+        {
+            Set<Challenge> updatedChallenges = new HashSet<>();
+
+            this.challengeCacheData.values().forEach(challengeObject -> {
+                if (challengeObject.getUniqueId().matches(".*[A-Z]+.*"))
+                {
+                    challengeObject.setUniqueId(challengeObject.getUniqueId().toLowerCase());
+                    challengeObject.setLevel(challengeObject.getLevel().toLowerCase());
+
+                    updatedChallenges.add(challengeObject);
+
+                    this.addon.logWarning("Challenge addon fixed your data for Challenge " +
+                        challengeObject.getUniqueId() +
+                        ". 1.14 does not allow to use capital letters in world names.");
+                }
+            });
+
+            Set<ChallengeLevel> updatedLevels = new HashSet<>();
+
+            this.levelCacheData.values().forEach(levelObject -> {
+                if (levelObject.getUniqueId().matches(".*[A-Z]+.*"))
+                {
+                    levelObject.setUniqueId(levelObject.getUniqueId().toLowerCase());
+                    levelObject.setWorld(levelObject.getWorld().toLowerCase());
+
+                    Set<String> correctNames = levelObject.getChallenges().stream().
+                        map(String::toLowerCase).
+                        collect(Collectors.toSet());
+
+                    levelObject.setChallenges(correctNames);
+
+                    updatedLevels.add(levelObject);
+
+                    this.addon.logWarning("Challenge addon fixed your data for Challenge Level " +
+                        levelObject.getUniqueId() +
+                        ". 1.14 does not allow to use capital letters in world names.");
+                }
+            });
+
+            // As at least one challenge or level was corrupted we must update all player data objects!
+            if (!updatedLevels.isEmpty() || !updatedChallenges.isEmpty())
+            {
+                List<ChallengesPlayerData> playerDataList = this.playersDatabase.loadObjects();
+
+                playerDataList.forEach(challengesPlayerData -> {
+
+                    Map<String, Integer> fixedChallengeStatus = new HashMap<>();
+                    challengesPlayerData.getChallengeStatus().forEach((challenge, count) ->
+                        fixedChallengeStatus.put(challenge.toLowerCase(), count));
+                    challengesPlayerData.setChallengeStatus(fixedChallengeStatus);
+
+                    Map<String, Long> fixedChallengeTimestamp = new HashMap<>();
+                    challengesPlayerData.getChallengesTimestamp().forEach((challenge, count) ->
+                        fixedChallengeTimestamp.put(challenge.toLowerCase(), count));
+                    challengesPlayerData.setChallengesTimestamp(fixedChallengeTimestamp);
+
+                    Set<String> fixedLevelsDone = new HashSet<>();
+                    challengesPlayerData.getLevelsDone().forEach(level -> fixedLevelsDone.add(level.toLowerCase()));
+                    challengesPlayerData.setLevelsDone(fixedLevelsDone);
+
+                    this.playersDatabase.saveObject(challengesPlayerData);
+
+                    this.addon.logWarning("Challenge addon fixed your data for PlayerData " +
+                            challengesPlayerData.getUniqueId() +
+                            ". 1.14 does not allow to use capital letters in world names.");
+                });
+            }
+        }
     }