Add special characters in URL

SpecialCharactersInUrlModule.cs

//Tested in EPiServer CMS 11
using System;
using System.Configuration;
using EPiServer.Framework;
using EPiServer.Framework.Initialization;
using EPiServer.ServiceLocation;
using EPiServer.Web;

namespace Alloy.Business
{
    [InitializableModule]
    [ModuleDependency(typeof(EPiServer.Web.InitializationModule))]
    public class SpecialCharactersInUrlModule : IConfigurableModule
    {
        private string specialCharacters;
        private string AllowedSpecialCharaters
        {
            get
            {
                if (string.IsNullOrEmpty(specialCharacters))
                {
                    //Add a value in App settings
                    //e.g. ßöäü
                    specialCharacters = Convert.ToString(ConfigurationManager.AppSettings["AllowedSpecialCharaters"]);
                }
                return specialCharacters;
            }
        }

        public void Initialize(InitializationEngine context)
        {
            //Do Nothing
        }

        public void Uninitialize(InitializationEngine context)
        {
            //Do Nothing
        }

        public void ConfigureContainer(ServiceConfigurationContext context)
        {
            context.Services.RemoveAll<UrlSegmentOptions>();
            context.Services.AddSingleton<UrlSegmentOptions>(segmentOption => new UrlSegmentOptions() { SupportIriCharacters = true, ValidUrlCharacters = $@"\p{L}0-9\-_~\.\${AllowedSpecialCharaters}" });
        }
    }
}