diff --git a/admin/change_current_user_password.php b/admin/change_current_user_password.php
index 0a25961..4515856 100644
--- a/admin/change_current_user_password.php
+++ b/admin/change_current_user_password.php
@@ -25,7 +25,7 @@ function can_process() {
 	$Auth_Result = hook_authenticate($_SESSION['wa_current_user']->username, $_POST['cur_password']);
 
 	if (!isset($Auth_Result))	// if not used external login: standard method
-		$Auth_Result = get_user_auth($_SESSION['wa_current_user']->username, md5($_POST['cur_password']));
+		$Auth_Result = authenticate_user($_SESSION['wa_current_user']->username, $_POST['cur_password']);
 
 	if (!$Auth_Result) {
 		display_error( _('Invalid password entered.'));
@@ -57,7 +57,7 @@ function can_process() {
 		if ($SysPrefs->allow_demo_mode)
 			display_warning(_('Password cannot be changed in demo mode.'));
 		else {
-			update_user_password($_SESSION['wa_current_user']->user, $_SESSION['wa_current_user']->username, md5($_POST['password']));
+			update_user_password($_SESSION['wa_current_user']->user, $_SESSION['wa_current_user']->username, password_hash($_POST['password'], PASSWORD_DEFAULT));
 			display_notification(_('Your password has been updated.'));
 		}
 		$Ajax->activate('_page_body');
@@ -86,4 +86,4 @@ function can_process() {
 
 submit_center( 'UPDATE_ITEM', _('Change password'), true, '',  'default');
 end_form();
-end_page();
\ No newline at end of file
+end_page();
diff --git a/admin/create_coy.php b/admin/create_coy.php
index 0ef1479..d7fb385 100644
--- a/admin/create_coy.php
+++ b/admin/create_coy.php
@@ -20,7 +20,7 @@
 
 page(_($help_context = 'Create/Update Company'));
 
-$comp_subdirs = array('images', 'pdf_files', 'backup','js_cache', 'reporting', 'attachments');
+$comp_subdirs = array('images', 'pdf_files', 'backup', 'js_cache', 'reporting', 'attachments');
 
 simple_page_mode(true);
 /*
@@ -107,7 +107,7 @@ function handle_submit($selected_id) {
 
 		$conn = $db_connections[$selected_id];
 		if (($db = db_create_db($conn)) === false) {
-			display_error(_('Error creating Database: ') . $conn['dbname'] . _(', Please create it manually'));
+			display_error(_('Error creating Database: ').$conn['dbname']._(', Please create it manually'));
 			$error = true;
 		}
 		else {
@@ -120,7 +120,7 @@ function handle_submit($selected_id) {
 			else {
 				if (!isset($_POST['admpassword']) || $_POST['admpassword'] == '')
 					$_POST['admpassword'] = 'password';
-				update_admin_password($conn, md5($_POST['admpassword']));
+				update_admin_password($conn, password_hash($_POST['admpassword']), PASSWORD_DEFAULT);
 			}
 		}
 		if ($error) {
@@ -350,4 +350,4 @@ function display_company_edit($selected_id) {
 
 end_form();
 
-end_page();
\ No newline at end of file
+end_page();
diff --git a/admin/db/users_db.inc b/admin/db/users_db.inc
index 4399a78..6f929fe 100644
--- a/admin/db/users_db.inc
+++ b/admin/db/users_db.inc
@@ -112,12 +112,29 @@ function delete_user($id) {
 
 //-----------------------------------------------------------------------------------------------
 
-function get_user_auth($user_id, $password) {
+function authenticate_user($user_id, $password) {
 
-	$sql = "SELECT * FROM ".TB_PREF."users WHERE user_id = ".db_escape($user_id)." AND"
-		." password=".db_escape($password);
+	$sql1 = "SELECT password FROM ".TB_PREF."users WHERE user_id = ".db_escape($user_id);
 
-	return db_num_rows(db_query($sql, 'could not get validate user login for '.$user_id)) != 0;
+	$result = db_query($sql1, 'could not get user login for '.$user_id);
+
+	if(db_num_rows($result) == 0)
+		return false;
+
+	$hash = db_fetch($result)[0];
+
+	// The user's password hash may have been created long ago by md5 password algorithm on the old NotrinosERP versions
+	if(password_verify($password, $hash) || $hash == md5($password)) {
+		if(password_needs_rehash($hash, PASSWORD_DEFAULT) === true) {
+			$new_hash = password_hash($password, PASSWORD_DEFAULT);
+			$sql2 = "UPDATE ".TB_PREF."users SET password = ".db_escape($new_hash)." WHERE user_id = ".db_escape($user_id);
+			db_query($sql2, 'could not update password hash for '.$user_id);
+		}
+
+		return true;
+	}
+
+	return false;
 }
 
 //-----------------------------------------------------------------------------------------------
diff --git a/admin/users.php b/admin/users.php
index 5fcfc2d..52fe844 100644
--- a/admin/users.php
+++ b/admin/users.php
@@ -56,12 +56,12 @@ function can_process($new) {
 			update_user_prefs($selected_id, get_post(array('user_id', 'real_name', 'phone', 'email', 'role_id', 'language', 'print_profile', 'rep_popup' => 0, 'pos')));
 
 			if ($_POST['password'] != '')
-				update_user_password($selected_id, $_POST['user_id'], md5($_POST['password']));
+				update_user_password($selected_id, $_POST['user_id'], password_hash($_POST['password'], PASSWORD_DEFAULT));
 
 			display_notification_centered(_('The selected user has been updated.'));
 		} 
 		else {
-			add_user($_POST['user_id'], $_POST['real_name'], md5($_POST['password']), $_POST['phone'], $_POST['email'], $_POST['role_id'], $_POST['language'], $_POST['print_profile'], check_value('rep_popup'), $_POST['pos']);
+			add_user($_POST['user_id'], $_POST['real_name'], password_hash($_POST['password'], PASSWORD_DEFAULT), $_POST['phone'], $_POST['email'], $_POST['role_id'], $_POST['language'], $_POST['print_profile'], check_value('rep_popup'), $_POST['pos']);
 			$id = db_insert_id();
 			// use current user display preferences as start point for new user
 			$prefs = $_SESSION['wa_current_user']->prefs->get_all();
diff --git a/includes/current_user.inc b/includes/current_user.inc
index 6584057..b1b6e20 100644
--- a/includes/current_user.inc
+++ b/includes/current_user.inc
@@ -69,11 +69,11 @@ class current_user {
 
 		// Use external authentication source if any.
 		// Keep in mind you need to have user data set for $loginname
-		// in FA users table anyway to successfully log in.
+		// in NotrinosERP users table anyway to successfully log in.
 		$Auth_Result = hook_authenticate($loginname, $password);
 
 		if (!isset($Auth_Result))	// if not used: standard method
-			$Auth_Result = get_user_auth($loginname, md5($password));
+			$Auth_Result = authenticate_user($loginname, $password);
 		if ($SysPrefs->login_delay > 0)
 			write_login_filelog($loginname, $Auth_Result);
 		if ($Auth_Result) {
@@ -151,7 +151,7 @@ class current_user {
 		if ($user != false) {
 
 			$password = generate_password();
-			$hash = md5($password);
+			$hash = password_hash($password);
 
 			update_user_password($user['id'], $user['user_id'], $hash);