diff --git a/config/services.yaml b/config/services.yaml
index 6bfbdfd2..3cacbea4 100644
--- a/config/services.yaml
+++ b/config/services.yaml
@@ -136,4 +136,10 @@ when@test:
             bind:
                 $publicDirectory: '%kernel.project_dir%/tests/Resources'
         App\Service\BookFileSystemManagerInterface:
-            alias: 'App\Tests\FileSystemManagerForTests'
\ No newline at end of file
+            alias: 'App\Tests\FileSystemManagerForTests'
+
+        App\Tests\TestClock:
+            public: true
+        'Gedmo\Timestampable\TimestampableListener':
+            calls:
+            - [ setClock, ['@App\Tests\TestClock'] ]
diff --git a/src/Controller/Kobo/Api/V1/LibraryController.php b/src/Controller/Kobo/Api/V1/LibraryController.php
index 4769b5ee..13517b7a 100644
--- a/src/Controller/Kobo/Api/V1/LibraryController.php
+++ b/src/Controller/Kobo/Api/V1/LibraryController.php
@@ -193,7 +193,7 @@ public function apiEndpoint(KoboDevice $koboDevice, SyncToken $syncToken, Reques
         $shouldContinue = $this->upstreamSyncMerger->merge($koboDevice, $response, $request);
 
         $httpResponse = $response->toJsonResponse();
-        $httpResponse->headers->set('x-kobo-sync', $shouldContinue || count($books) < $count ? 'continue' : 'done');
+        $httpResponse->headers->set(KoboDevice::KOBO_SYNC_SHOULD_CONTINUE_HEADER, $shouldContinue || count($books) < $count ? 'continue' : 'done');
 
         // Once the response is generated, we update the list of synced books
         // If you do this before, the logic will be broken
diff --git a/src/Entity/KoboDevice.php b/src/Entity/KoboDevice.php
index 4d72e558..2beda821 100644
--- a/src/Entity/KoboDevice.php
+++ b/src/Entity/KoboDevice.php
@@ -20,6 +20,7 @@ class KoboDevice
     public const KOBO_DEVICE_ID_HEADER = 'X-Kobo-Deviceid';
     public const KOBO_DEVICE_MODEL_HEADER = 'X-Kobo-Devicemodel';
     public const KOBO_SYNC_TOKEN_HEADER = 'kobo-synctoken';
+    public const KOBO_SYNC_SHOULD_CONTINUE_HEADER = 'x-kobo-sync';
 
     #[ORM\Id]
     #[ORM\GeneratedValue]
diff --git a/src/Kobo/Response/SyncResponse.php b/src/Kobo/Response/SyncResponse.php
index 0a5835db..1412908f 100644
--- a/src/Kobo/Response/SyncResponse.php
+++ b/src/Kobo/Response/SyncResponse.php
@@ -192,7 +192,7 @@ private function getNewTags(): array
     private function getChangedTag(): array
     {
         $shelves = array_filter($this->shelves, function (Shelf $shelf) {
-            return $this->syncToken->lastModified instanceof \DateTimeInterface && $shelf->getUpdated() < $this->syncToken->lastModified;
+            return $this->syncToken->tagLastModified instanceof \DateTimeInterface && $shelf->getUpdated() >= $this->syncToken->tagLastModified;
         });
 
         return array_map(function (Shelf $shelf) {
diff --git a/src/Kobo/Response/SyncResponseHelper.php b/src/Kobo/Response/SyncResponseHelper.php
index 9cc1ddfd..a1e4259a 100644
--- a/src/Kobo/Response/SyncResponseHelper.php
+++ b/src/Kobo/Response/SyncResponseHelper.php
@@ -23,13 +23,11 @@ public function isChangedEntitlement(Book $book, KoboDevice $koboDevice, SyncTok
             return false;
         }
 
-        if ($this->isChangedReadingState($book, $koboDevice, $syncToken)) {
+        if (!$syncToken->lastModified instanceof \DateTimeInterface) {
             return false;
         }
 
-        return ($syncToken->lastModified instanceof \DateTimeInterface && $book->getUpdated() instanceof \DateTimeInterface
-            && $book->getUpdated() >= $syncToken->lastModified)
-            || ($syncToken->lastCreated instanceof \DateTimeInterface && $book->getCreated() >= $syncToken->lastCreated);
+        return $book->getUpdated() >= $syncToken->lastModified;
     }
 
     public function isNewEntitlement(Book $book, SyncToken $syncToken): bool
@@ -39,9 +37,14 @@ public function isNewEntitlement(Book $book, SyncToken $syncToken): bool
 
     public function isChangedReadingState(Book $book, KoboDevice $koboDevice, SyncToken $syncToken): bool
     {
-        if ($this->isNewEntitlement($book, $syncToken)) {
+        if ($this->isChangedEntitlement($book, $koboDevice, $syncToken)) {
             return false;
         }
+
+        if (!$syncToken->readingStateLastModified instanceof \DateTimeInterface) {
+            return false;
+        }
+
         $lastInteraction = $book->getLastInteraction($koboDevice->getUser());
 
         return ($lastInteraction instanceof BookInteraction) && $lastInteraction->getUpdated() >= $syncToken->readingStateLastModified;
diff --git a/src/Kobo/UpstreamSyncMerger.php b/src/Kobo/UpstreamSyncMerger.php
index 325235d9..0ea95f2c 100644
--- a/src/Kobo/UpstreamSyncMerger.php
+++ b/src/Kobo/UpstreamSyncMerger.php
@@ -80,6 +80,6 @@ private function parseJson(Response $response): array
 
     private function shouldContinue(Response $response): bool
     {
-        return $response->headers->get('x-kobo-sync') === 'continue';
+        return $response->headers->get(KoboDevice::KOBO_SYNC_SHOULD_CONTINUE_HEADER) === 'continue';
     }
 }
diff --git a/src/Repository/BookRepository.php b/src/Repository/BookRepository.php
index 7333ad3a..a6becb0b 100644
--- a/src/Repository/BookRepository.php
+++ b/src/Repository/BookRepository.php
@@ -392,24 +392,28 @@ private function getChangedBooksQueryBuilder(KoboDevice $koboDevice, SyncToken $
             ->setParameter('koboDevice', $koboDevice)
             ->setParameter('extension', 'epub') // Pdf is not supported by kobo sync
             ->groupBy('book.id');
+        $bigOr = $qb->expr()->orX();
+
         if ($syncToken->lastCreated instanceof \DateTimeInterface) {
-            $qb->andWhere($qb->expr()->orX(
+            $bigOr->addMultiple([
                 $qb->expr()->isNull('koboSyncedBooks.created'),
                 $qb->expr()->gte('book.created', ':lastCreated'),
-            ))
-            ->setParameter('lastCreated', $syncToken->lastCreated);
+            ]);
+            $qb->setParameter('lastCreated', $syncToken->lastCreated);
         }
 
         if ($syncToken->lastModified instanceof \DateTimeInterface) {
-            $qb->andWhere($qb->expr()->orX(
+            $bigOr->addMultiple([
                 'book.updated > :lastModified',
                 'book.created  > :lastModified',
                 'koboSyncedBooks.updated > :lastModified',
                 $qb->expr()->isNull('koboSyncedBooks.updated'),
-            ));
+            ]);
             $qb->setParameter('lastModified', $syncToken->lastModified);
         }
 
+        $qb->andWhere($bigOr);
+
         $qb->orderBy('book.updated');
         if ($syncToken->filters['PrioritizeRecentReads'] ?? false) {
             $qb->orderBy('bookInteractions.updated', 'ASC');
diff --git a/tests/Controller/Kobo/KoboSyncControllerTest.php b/tests/Controller/Kobo/KoboSyncControllerTest.php
index 6dabc9f9..4ee7d51b 100644
--- a/tests/Controller/Kobo/KoboSyncControllerTest.php
+++ b/tests/Controller/Kobo/KoboSyncControllerTest.php
@@ -3,6 +3,7 @@
 namespace App\Tests\Controller\Kobo;
 
 use App\DataFixtures\BookFixture;
+use App\Entity\KoboDevice;
 use App\Entity\KoboSyncedBook;
 use App\Kobo\Response\MetadataResponseService;
 use App\Kobo\SyncToken;
@@ -10,6 +11,7 @@
 use App\Service\KoboSyncTokenExtractor;
 use App\Tests\Contraints\AssertHasDownloadWithFormat;
 use App\Tests\Contraints\JSONIsValidSyncResponse;
+use App\Tests\TestClock;
 
 class KoboSyncControllerTest extends AbstractKoboControllerTest
 {
@@ -18,7 +20,7 @@ protected function tearDown(): void
         $this->getKoboStoreProxy()->setClient(null);
         $this->getKoboProxyConfiguration()->setEnabled(false);
         $this->getEntityManager()->getRepository(KoboSyncedBook::class)->deleteAllSyncedBooks(1);
-
+        $this->getService(TestClock::class)->setTime(null);
         parent::tearDown();
     }
 
@@ -117,7 +119,7 @@ public function testSyncControllerPaginated() : void
             }, $pageNum), 'Response is not a valid sync response for page '.$pageNum);
 
             $expectedContinueHeader = $pageNum === $numberOfPages ? 'done' : 'continue';
-            self::assertResponseHeaderSame('x-kobo-sync', $expectedContinueHeader, 'x-kobo-sync is invalid');
+            self::assertResponseHeaderSame(KoboDevice::KOBO_SYNC_SHOULD_CONTINUE_HEADER, $expectedContinueHeader, 'x-kobo-sync is invalid');
         }
 
         $count = $this->getEntityManager()->getRepository(KoboSyncedBook::class)->count(['koboDevice' => 1]);
@@ -132,6 +134,46 @@ public function testSyncControllerPaginated() : void
 
     }
 
+    /**
+     * @covers pagination2
+     * @throws \JsonException
+     */
+    public function testSyncControllerEdited() : void{
+        $client = static::getClient();
+
+        // Create an old sync token
+        $clock = $this->getService(TestClock::class)
+            ->setTime(new \DateTimeImmutable('1 hour ago'));
+        $syncToken = new SyncToken();
+        $syncToken->lastCreated = $clock->now();
+        $syncToken->lastModified = $clock->now();
+        $syncToken->tagLastModified = $clock->now();
+
+        // Sync all the books
+        $headers = $this->getService(KoboSyncTokenExtractor::class)->getTestHeader($syncToken);
+        $client?->request('GET', '/kobo/' . $this->accessKey . '/v1/library/sync', [], [], $headers);
+        self::assertResponseIsSuccessful();
+
+        // Edit the book detail 30 minutes ago
+        $clock->setTime(new \DateTimeImmutable('30 minutes ago'));
+        $book = $this->getBook();
+        $book->setSlug($book->getSlug()."..");
+        $this->getEntityManager()->flush();
+
+        // Restore the real time
+        $clock->setTime(null);
+
+        // Make sure the book has changed.
+        $client?->request('GET', '/kobo/' . $this->accessKey . '/v1/library/sync', [], [], $headers);
+        self::assertResponseIsSuccessful();
+        self::assertThat(self::getJsonResponse(), new JSONIsValidSyncResponse([
+            'ChangedEntitlement' => 1
+        ]));
+
+        self::assertResponseHeaderSame(KoboDevice::KOBO_SYNC_SHOULD_CONTINUE_HEADER, 'done', 'x-kobo-sync is invalid');
+    }
+
+
     public function testSyncControllerWithRemote() : void
     {
         $client = static::getClient();
diff --git a/tests/TestClock.php b/tests/TestClock.php
new file mode 100644
index 00000000..30fcd8c0
--- /dev/null
+++ b/tests/TestClock.php
@@ -0,0 +1,21 @@
+<?php
+namespace App\Tests;
+use Psr\Clock\ClockInterface;
+
+class TestClock implements ClockInterface
+{
+
+    private ?\DateTimeImmutable $now = null;
+
+    public function now(): \DateTimeImmutable
+    {
+        return $this->now ?? new \DateTimeImmutable();
+    }
+
+    public function setTime(?\DateTimeImmutable $now): self
+    {
+        $this->now = $now;
+
+        return $this;
+    }
+}
\ No newline at end of file