Does anyone know if Adobe Lifecycle Designer ES4 is still in active development or if it is in a long term support state now?
ES4 is an end of core support but extended support for ES4 still exists. As Scott mentioned you can look towards upgrading to AEM forms, 6.4 being the latest version.
You can check the end of Life matrix of the products here:
All Apps Help | Products and technical support periods
More AEM Forms content being moved to AEM Forms for OSGi and Adaptive Forms.