IdentityServer 4 RavenDB stores

Enable Document Expiration

await store.Maintenance.SendAsync(new ConfigureExpirationOperation(new ExpirationConfiguration
{
    Disabled = false,
    DeleteFrequencyInSec = 60
}));

Register Claims and Principals custom IdentityServer serializers

documentStore.Conventions.CustomizeJsonSerializer += (JsonSerializer serializer) =>
{
    serializer.Converters.Add(new ClaimConverter());
    serializer.Converters.Add(new ClaimsPrincipalConverter());
};