Liferay Freemarker datetime format with 4-digit year

four-digit-year.ftl

<#setting time_zone=timeZone.ID>
<#setting locale=locale.toString()>
<#setting datetime_format="MM/dd/yyyy">

<ul>
   <#list entries as entry>
      <li><li>${entry.title} - ${entry.modifiedDate?datetime}</li></li>
   </#list>
</ul>

OK, now I understand what you want to achieve. In that case I think you might need to use conditional construction that sets the datetime_format according to the current portal locale.

<#setting time_zone=timeZone.ID>
<#setting locale=locale.toString()>

<#assign portalLocale=locale.toString()>
<#if portalLocale="en_US">
  <#setting datetime_format="MM/dd/yyyy">
<#else>
  <#setting datetime_format="dd/MM/yyyy">
</#if>

${.now?datetime}

Ok, not very confortable if I have to manage a portal supporting 30 different languages, but I got the point.
Thank you!