diff --git a/migrations/api_v3/challenges.js b/migrations/api_v3/challenges.js
index a650e26188..85a019cc7d 100644
--- a/migrations/api_v3/challenges.js
+++ b/migrations/api_v3/challenges.js
@@ -17,6 +17,7 @@ var mongoose = require('mongoose');
 var _ = require('lodash');
 var uuid = require('uuid');
 var consoleStamp = require('console-stamp');
+var fs = require('fs');
 
 // Add timestamps to console messages
 consoleStamp(console);
@@ -48,6 +49,8 @@ var BATCH_SIZE = 1000;
 var processedChallenges = 0;
 var totoalProcessedTasks = 0;
 
+var newTasksIds = {}; // a map of old id -> [new id, challengeId]
+
 // Only process challenges that fall in a interval ie -> up to 0000-4000-0000-0000
 var AFTER_CHALLENGE_ID = nconf.get('AFTER_CHALLENGE_ID');
 var BEFORE_CHALLENGE_ID = nconf.get('BEFORE_CHALLENGE_ID');
@@ -109,23 +112,33 @@ function processChallenges (afterId) {
       if (!oldChallenge.group) throw new Error('challenge.group is required');
       if (!oldChallenge.leader) throw new Error('challenge.leader is required');
 
+      delete oldChallenge.id;
+
       var newChallenge = new NewChallenge(oldChallenge);
 
       newChallenge.createdAt = createdAt;
 
       oldTasks.forEach(function (oldTask) {
-        oldTask._id = uuid.v4(); // TODO keep the old uuid unless duplicated
+        oldTask._id = uuid.v4();
         oldTask.legacyId = oldTask.id; // store the old task id
         delete oldTask.id;
 
+        oldTask.challenge = oldTask.challenge || {};
+        oldTask.challenge.id = newChallenge._id;
+
+        if (newTasksIds[oldTask.legacyId + '-' + newChallenge._id]) {
+          throw new Error('duplicate :(');
+        } else {
+          newTasksIds[oldTask.legacyId + '-' + newChallenge._id] = oldTask._id;
+        }
+
         oldTask.tags = _.map(oldTask.tags || {}, function (tagPresent, tagId) {
           return tagPresent && tagId;
         });
 
         if (!oldTask.text) oldTask.text = 'task text'; // required
 
-        oldTask.challenge = oldTask.challenge || {};
-        oldTask.challenge.id = oldChallenge._id;
+        oldTask.createdAt = oldTask.dateCreated;
 
         newChallenge.tasksOrder[`${oldTask.type}s`].push(oldTask._id);
         if (oldTask.completed) oldTask.completed = false;
@@ -155,6 +168,8 @@ function processChallenges (afterId) {
     if (lastChallenge) {
       return processChallenges(lastChallenge);
     } else {
+      console.log('Writing newTasksIds.json...')
+      fs.writeFileSync('newTasksIds.json', JSON.stringify(newTasksIds, null, 4), 'utf8');
       return console.log('Done!');
     }
   });
diff --git a/migrations/api_v3/challengesMembers.js b/migrations/api_v3/challengesMembers.js
index f5c1532660..98a42964fa 100644
--- a/migrations/api_v3/challengesMembers.js
+++ b/migrations/api_v3/challengesMembers.js
@@ -86,6 +86,13 @@ function processChallenges (afterId) {
       lastChallenge = oldChallenges[oldChallenges.length - 1]._id;
     }
 
+    // Tyler Renelle
+    oldChallenge.members.forEach(function (id, index) {
+      if (id === '9') {
+        oldChallenge.members[index] = '00000000-0000-4000-9000-000000000000';
+      }
+    });
+
     oldChallenges.forEach(function (oldChallenge) {
       promises.push(newUserCollection.updateMany({
         _id: {$in: oldChallenge.members},
diff --git a/migrations/api_v3/groups.js b/migrations/api_v3/groups.js
index 2fa465c67e..d013924cea 100644
--- a/migrations/api_v3/groups.js
+++ b/migrations/api_v3/groups.js
@@ -144,6 +144,13 @@ function processGroups (afterId) {
       }
 
       if (oldGroup.members) {
+        // Tyler Renelle
+        oldGroup.members.forEach(function (id, index) {
+          if (id === '9') {
+            oldGroup.members[index] = '00000000-0000-4000-9000-000000000000';
+          }
+        });
+
         promises.push(newUserCollection.updateMany({
           _id: {$in: oldGroup.members},
         }, updateMembers, {multi: true}));
diff --git a/migrations/api_v3/users.js b/migrations/api_v3/users.js
index ecc502025e..abf3e12e26 100644
--- a/migrations/api_v3/users.js
+++ b/migrations/api_v3/users.js
@@ -51,6 +51,12 @@ var BATCH_SIZE = 1000;
 var processedUsers = 0;
 var totoalProcessedTasks = 0;
 
+var challengeTaskWithMatchingId = 0;
+var challengeTaskNoMatchingId = 0;
+
+// Load the new tasks ids for challenges tasks
+var newTasksIds = require('./newTasksIds.json');
+
 // Only process users that fall in a interval ie up to -> 0000-4000-0000-0000
 var AFTER_USER_ID = nconf.get('AFTER_USER_ID');
 var BEFORE_USER_ID = nconf.get('BEFORE_USER_ID');
@@ -110,6 +116,8 @@ function processUsers (afterId) {
       delete oldUser.rewards;
       delete oldUser.todos;
 
+      delete oldUser.id;
+
       oldUser.tags = oldUser.tags.map(function (tag) {
         return {
           id: tag.id,
@@ -132,10 +140,24 @@ function processUsers (afterId) {
 
         oldTask.challenge = oldTask.challenge || {};
         if (oldTask.challenge.id) {
-          oldTask.challenge.taskId = oldTask.legacyId;
+          if (oldTask.challenge.broken) {
+            oldTask.challenge.taskId = oldTask.legacyId;
+          } else {
+            var newId = newTasksIds[oldTask.legacyId + '-' + oldTask.challenge.id];
+
+            // Challenges' tasks ids changed
+            if (!newId && !oldTask.challenge.broken) {
+              challengeTaskNoMatchingId++;
+              oldTask.challenge.taskId = oldTask.legacyId;
+              oldTask.challenge.broken = 'CHALLENGE_TASK_NOT_FOUND';
+            } else {
+              challengeTaskWithMatchingId++;
+              oldTask.challenge.taskId = newId;
+            }
+          }
         }
 
-        oldTask.createdAt = old.dateCreated;
+        oldTask.createdAt = oldTask.dateCreated;
 
         if (!oldTask.text) oldTask.text = 'task text'; // required
         oldTask.tags = _.map(oldTask.tags, function (tagPresent, tagId) {
@@ -179,6 +201,8 @@ function processUsers (afterId) {
     processedUsers += oldUsers.length;
 
     console.log(`Saved ${oldUsers.length} users and their tasks.`);
+    console.log('Challenges\' tasks no matching id: ', challengeTaskNoMatchingId);
+    console.log('Challenges\' tasks with matching id: ', challengeTaskWithMatchingId);
 
     if (lastUser) {
       return processUsers(lastUser);