diff --git a/build.gradle b/build.gradle
index ea54276..b6b611a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,5 @@
 plugins {
-    id 'org.springframework.boot' version '2.7.16'
+    id 'org.springframework.boot' version '2.7.17'
     id 'io.spring.dependency-management' version '1.1.3'
     id 'java'
 }
@@ -43,7 +43,7 @@ dependencies {
     //implementation group: 'jakarta.validation', name: 'jakarta.validation-api', version: '3.0.2'
 
     // https://mvnrepository.com/artifact/com.google.guava/guava
-    implementation group: 'com.google.guava', name: 'guava', version: '32.1.2-jre'
+    implementation group: 'com.google.guava', name: 'guava', version: '32.1.3-jre'
 
     // https://mvnrepository.com/artifact/org.apache.commons/commons-lang3
     implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.13.0'
@@ -113,14 +113,14 @@ dependencies {
     implementation 'com.fasterxml.woodstox:woodstox-core:6.5.1'
 
     // https://mvnrepository.com/artifact/org.json/json
-    implementation 'org.json:json:20230618'
+    implementation 'org.json:json:20231013'
 
     // https://mvnrepository.com/artifact/com.google.code.gson/gson
     implementation 'com.google.code.gson:gson:2.10.1'
 
 
     // https://mvnrepository.com/artifact/io.micrometer/micrometer-registry-prometheus
-    runtimeOnly 'io.micrometer:micrometer-registry-prometheus:1.11.4'
+    runtimeOnly 'io.micrometer:micrometer-registry-prometheus:1.11.5'
 
     testImplementation 'org.springframework.security:spring-security-test'
     testImplementation "org.springframework.boot:spring-boot-starter-test"
diff --git a/src/main/java/eu/openaire/urls_controller/components/ScheduledTasks.java b/src/main/java/eu/openaire/urls_controller/components/ScheduledTasks.java
index 489fb0e..866d134 100644
--- a/src/main/java/eu/openaire/urls_controller/components/ScheduledTasks.java
+++ b/src/main/java/eu/openaire/urls_controller/components/ScheduledTasks.java
@@ -24,7 +24,9 @@ import org.springframework.stereotype.Component;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileReader;
+import java.util.ArrayList;
 import java.util.Date;
+import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
@@ -100,6 +102,8 @@ public class ScheduledTasks {
 
         int numFailedTasks = 0;
 
+        List<Future<Boolean>> futuresToDelete = new ArrayList<>(sizeOfFutures);
+
         for ( int i=0; i < sizeOfFutures; ++i ) {
             Future<Boolean> future = null;
             try {
@@ -121,10 +125,13 @@ public class ScheduledTasks {
                 // Only here, the "future" will be null.
             } finally {
                 if ( future != null )
-                    UrlsController.futuresOfBackgroundTasks.remove(future); // We do not need it anymore. This is the safest way to delete them without removing newly added futures as well.
+                    futuresToDelete.add(future);    // Do not delete them directly here, as the indexes will get messed up and we will get "IOOBE".
             }
         }
 
+        for ( Future<Boolean> future : futuresToDelete )
+            UrlsController.futuresOfBackgroundTasks.remove(future); // We do not need it anymore. This is the safest way to delete them without removing newly added futures as well.
+
         if ( numFailedTasks > 0 )
             logger.warn(numFailedTasks + " out of " + sizeOfFutures + " tasks have failed!");
         else