Fatal error: Uncaught Error: Call to undefined function mb_regex_encoding() in /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/plugins/shared.mb_str_replace.php:47
Stack trace:
#0 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/plugins/modifier.replace.php(34): smarty_mb_str_replace()
#1 /var/www/html/cache/t_compile/13376d7934b5f251160733e5e3c8b2ff6a1e1f24^164bd5a4f3891532cf93e9d19911fe9cb3308efd_0.app.layoutsbackend.tpl.php(31): smarty_modifier_replace()
#2 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_resource_base.php(123): content_68924c9f129981_58066386()
#3 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_compiled.php(114): Smarty_Template_Resource_Base->getRenderedTemplateCode()
#4 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php(217): Smarty_Template_Compiled->render()
#5 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php(386): Smarty_Internal_Template->render()
#6 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_runtime_inheritance.php(115): Smarty_Internal_Template->_subTemplateRender()
#7 /var/www/html/cache/t_compile/13376d7934b5f251160733e5e3c8b2ff6a1e1f24^8e26d4d5b957a6848a96c58ac27d2fddb2c40f9a_0.app.installinstall.tpl.php(34): Smarty_Internal_Runtime_Inheritance->endChild()
#8 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_resource_base.php(123): content_68924c9f104ee5_59915258()
#9 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_compiled.php(114): Smarty_Template_Resource_Base->getRenderedTemplateCode()
#10 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php(217): Smarty_Template_Compiled->render()
#11 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_templatebase.php(238): Smarty_Internal_Template->render()
#12 /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_templatebase.php(134): Smarty_Internal_TemplateBase->_execute()
#13 /var/www/html/lib/pkp/classes/template/PKPTemplateManager.php(1505): Smarty_Internal_TemplateBase->display()
#14 /var/www/html/lib/pkp/classes/form/Form.php(214): PKP\template\PKPTemplateManager->display()
#15 /var/www/html/lib/pkp/classes/form/Form.php(156): PKP\form\Form->fetch()
#16 /var/www/html/lib/pkp/classes/install/form/MaintenanceForm.php(51): PKP\form\Form->display()
#17 /var/www/html/lib/pkp/classes/install/form/InstallForm.php(124): PKP\install\form\MaintenanceForm->display()
#18 /var/www/html/lib/pkp/pages/install/InstallHandler.php(58): PKP\install\form\InstallForm->display()
#19 [internal function]: PKP\pages\install\InstallHandler->index()
#20 /var/www/html/lib/pkp/classes/core/PKPRouter.php(327): call_user_func()
#21 /var/www/html/lib/pkp/classes/core/PKPPageRouter.php(249): PKP\core\PKPRouter->_authorizeInitializeAndCallRequest()
#22 /var/www/html/lib/pkp/classes/core/Dispatcher.php(157): PKP\core\PKPPageRouter->route()
#23 /var/www/html/lib/pkp/classes/core/PKPApplication.php(426): PKP\core\Dispatcher->dispatch()
#24 /var/www/html/index.php(21): PKP\core\PKPApplication->execute()
#25 {main}
thrown in /var/www/html/lib/pkp/lib/vendor/smarty/smarty/libs/plugins/shared.mb_str_replace.php on line 47