Yesterday, the Maréchalet de la Cour announced that the succession to the throne has been modified. On 16 September 2010, The Grand Duke modified the internal regulations of the House of Luxembourg-Nassau making succession to the throne gender neutral. The change will begin with the descendants of Grand Duke Henri. The press release also states that the internal regulations of the house are undergoing further undisclosed modernization.
Luxembourg based news papers indicate that the changes to the succession are awaiting legislative approval (rubber stamping, they call it). They further state that succession will be based on direct constitutional provisions (like everyone expected) and not the Nassau Family Pact or any internal regulations of the Grand Ducal House. That isn't exactly what I gathered from the full text of the press release, which mainly focused on the changes made via the house law/family pact.
Unfortunately, the act of 16 September 2010 has yet to be published nor have any other details concerning the modernization of the "internal regulations of the House of Luxembourg-Nassau."
The information released leaves many questions unanswered: does the gender neutral succession include other branches (simply beginning with Henri's heirs) or does it exclude them, just legitimate descendants of a marriage or a marriage with consent and are any new provisions made to regain lost rights of succession (Belgium and Monaco style)? Does anyone come after Prince Sebastien in the line of succession, and if so, is it Princess Marie-Astrid or Prince Guillaume? An entirely new house law along the lines of the wonderfully thorough house laws of Liechtenstein would be smashing.
You can read the English article in Wort and view the press release curtsy of RTL. I would also point out that the last change the succession (other than renunciations) was in July 1907, contrary to Wort's indication that the succession hasn't changed since 1783.