diff --git a/application/views/layouts/backend/backend_header.php b/application/views/layouts/backend/backend_header.php
index 0e424930..64db960d 100755
--- a/application/views/layouts/backend/backend_header.php
+++ b/application/views/layouts/backend/backend_header.php
@@ -12,7 +12,7 @@
         <small>Open Source Appointment Scheduler</small>
     </div>
 
-    <button type="button" class="navbar-toggler" data-toggle="collapse" data-target="#header-menu">
+    <button type="button" class="navbar-toggler" data-bs-toggle="collapse" data-target="#header-menu">
         <span class="sr-only">Toggle navigation</span>
         <span class="navbar-toggler-icon"></span>
     </button>
@@ -42,7 +42,7 @@
             <?php $hidden = ($privileges[PRIV_SERVICES]['view'] == TRUE) ? '' : 'd-none' ?>
             <?php $active = ($active_menu == PRIV_SERVICES) ? 'active' : '' ?>
             <li class="nav-item dropdown <?= $active . $hidden ?>">
-                <a class="nav-link dropdown-toggle" href="#" data-toggle="dropdown" 
+                <a class="nav-link dropdown-toggle" href="#" data-bs-toggle="dropdown" 
                    data-tippy-content="<?= lang('manage_services_hint') ?>">
                     <i class="fas fa-business-time mr-2"></i>
                     <?= lang('services') ?>
@@ -60,7 +60,7 @@
             <?php $hidden = ($privileges[PRIV_USERS]['view'] == TRUE) ? '' : 'd-none' ?>
             <?php $active = ($active_menu == PRIV_USERS) ? 'active' : '' ?>
             <li class="nav-item dropdown <?= $active . $hidden ?>">
-                <a class="nav-link dropdown-toggle" href="#" data-toggle="dropdown"
+                <a class="nav-link dropdown-toggle" href="#" data-bs-toggle="dropdown"
                    data-tippy-content="<?= lang('manage_users_hint') ?>">
                     <i class="fas fa-business-time mr-2"></i>
                     <?= lang('users') ?>
@@ -82,7 +82,7 @@
                 || $privileges[PRIV_USER_SETTINGS]['view'] == TRUE) ? '' : 'd-none' ?>
             <?php $active = ($active_menu == PRIV_SYSTEM_SETTINGS) ? 'active' : '' ?>
             <li class="nav-item dropdown <?= $active . $hidden ?>">
-                <a class="nav-link dropdown-toggle" href="#" data-toggle="dropdown"
+                <a class="nav-link dropdown-toggle" href="#" data-bs-toggle="dropdown"
                    data-tippy-content="<?= lang('settings_hint') ?>">
                     <i class="fas fa-cogs mr-2"></i>
                     <?= lang('settings') ?>
diff --git a/application/views/layouts/booking/booking_header.php b/application/views/layouts/booking/booking_header.php
index 73866dc7..51351fcc 100644
--- a/application/views/layouts/booking/booking_header.php
+++ b/application/views/layouts/booking/booking_header.php
@@ -13,15 +13,15 @@
             <strong>1</strong>
         </div>
 
-        <div id="step-2" class="book-step" data-toggle="tooltip"
+        <div id="step-2" class="book-step" data-bs-toggle="tooltip"
              data-tippy-content="<?= lang('appointment_date_and_time') ?>">
             <strong>2</strong>
         </div>
-        <div id="step-3" class="book-step" data-toggle="tooltip"
+        <div id="step-3" class="book-step" data-bs-toggle="tooltip"
              data-tippy-content="<?= lang('customer_information') ?>">
             <strong>3</strong>
         </div>
-        <div id="step-4" class="book-step" data-toggle="tooltip"
+        <div id="step-4" class="book-step" data-bs-toggle="tooltip"
              data-tippy-content="<?= lang('appointment_confirmation') ?>">
             <strong>4</strong>
         </div>
diff --git a/application/views/pages/booking/booking_step_3.php b/application/views/pages/booking/booking_step_3.php
index efedc4aa..f9ffb22e 100644
--- a/application/views/pages/booking/booking_step_3.php
+++ b/application/views/pages/booking/booking_step_3.php
@@ -81,7 +81,7 @@
             <label class="form-check-label" for="accept-to-terms-and-conditions">
                 <?= strtr(lang('read_and_agree_to_terms_and_conditions'),
                     [
-                        '{$link}' => '<a href="#" data-toggle="modal" data-target="#terms-and-conditions-modal">',
+                        '{$link}' => '<a href="#" data-bs-toggle="modal" data-target="#terms-and-conditions-modal">',
                         '{/$link}' => '</a>'
                     ])
                 ?>
@@ -95,7 +95,7 @@
             <label class="form-check-label" for="accept-to-privacy-policy">
                 <?= strtr(lang('read_and_agree_to_privacy_policy'),
                     [
-                        '{$link}' => '<a href="#" data-toggle="modal" data-target="#privacy-policy-modal">',
+                        '{$link}' => '<a href="#" data-bs-toggle="modal" data-target="#privacy-policy-modal">',
                         '{/$link}' => '</a>'
                     ])
                 ?>
diff --git a/application/views/pages/calendar/calendar_page.php b/application/views/pages/calendar/calendar_page.php
index 60ef9488..88460643 100755
--- a/application/views/pages/calendar/calendar_page.php
+++ b/application/views/pages/calendar/calendar_page.php
@@ -91,7 +91,7 @@
                     <span><?= lang('synchronize') ?></span>
                 </button>
 
-                <button id="enable-sync" class="btn btn-light" data-toggle="button"
+                <button id="enable-sync" class="btn btn-light" data-bs-toggle="button"
                         data-tippy-content="<?= lang('enable_appointment_sync_hint') ?>">
                     <i class="fas fa-calendar-alt mr-2"></i>
                     <span><?= lang('enable_sync') ?></span>
@@ -105,7 +105,7 @@
                         <?= lang('appointment') ?>
                     </button>
 
-                    <button class="btn btn-light dropdown-toggle" id="insert-dropdown" data-toggle="dropdown">
+                    <button class="btn btn-light dropdown-toggle" id="insert-dropdown" data-bs-toggle="dropdown">
                         <span class="caret"></span>
                         <span class="sr-only">Toggle Dropdown</span>
                     </button>
diff --git a/application/views/pages/providers/providers_page.php b/application/views/pages/providers/providers_page.php
index 644aba06..d1a10e8e 100755
--- a/application/views/pages/providers/providers_page.php
+++ b/application/views/pages/providers/providers_page.php
@@ -97,12 +97,12 @@
 
             <ul class="nav nav-pills switch-view">
                 <li class="nav-item">
-                    <a class="nav-link active" href="#details" data-toggle="tab">
+                    <a class="nav-link active" href="#details" data-bs-toggle="tab">
                         <?= lang('details') ?>
                     </a>
                 </li>
                 <li class="nav-item">
-                    <a class="nav-link" href="#working-plan" data-toggle="tab">
+                    <a class="nav-link" href="#working-plan" data-bs-toggle="tab">
                         <?= lang('working_plan') ?>
                     </a>
                 </li>
diff --git a/application/views/pages/users/users_page.php b/application/views/pages/users/users_page.php
index 23daa501..43e2a120 100755
--- a/application/views/pages/users/users_page.php
+++ b/application/views/pages/users/users_page.php
@@ -65,17 +65,17 @@
     <!-- PAGE NAVIGATION -->
     <ul class="nav nav-pills">
         <li class="nav-item">
-            <a class="nav-link active" href="#providers" data-toggle="tab">
+            <a class="nav-link active" href="#providers" data-bs-toggle="tab">
                 <?= lang('providers') ?>
             </a>
         </li>
         <li class="nav-item">
-            <a class="nav-link" href="#secretaries" data-toggle="tab">
+            <a class="nav-link" href="#secretaries" data-bs-toggle="tab">
                 <?= lang('secretaries') ?>
             </a>
         </li>
         <li class="nav-item">
-            <a class="nav-link" href="#admins" data-toggle="tab">
+            <a class="nav-link" href="#admins" data-bs-toggle="tab">
                 <?= lang('admins') ?>
             </a>
         </li>
@@ -142,12 +142,12 @@
 
                     <ul class="nav nav-pills switch-view">
                         <li class="nav-item">
-                            <a class="nav-link active" href="#details" data-toggle="tab">
+                            <a class="nav-link active" href="#details" data-bs-toggle="tab">
                                 <?= lang('details') ?>
                             </a>
                         </li>
                         <li class="nav-item">
-                            <a class="nav-link" href="#working-plan" data-toggle="tab">
+                            <a class="nav-link" href="#working-plan" data-bs-toggle="tab">
                                 <?= lang('working_plan') ?>
                             </a>
                         </li>