As per the Wikipedia article on the Alsatian language (https://en.wikipedia.org/wiki/Alsatian_dialect#Orthography) the orthography includes the latin letters A,B,C ... X,Y,Z and the following vowels with diacritics with the corresponding IPA below.
But as per the "Office pour la langue et le cultures d'alsace et de moselle" (http://www.olcalsace.org/) the official(?) body within France for language and culture for the Alsace region. The orthography for Alsatian (all/most dialects) follow the ORTHAL system (http://www.orthal.fr/index.html & https://fr.wikipedia.org/wiki/Orthal)
Latest specification (http://www.orthal.fr/ORTHAL_2016.pdf) & Explanatory document (http://www.olcalsace.org/sites/default/files/documents/synthese_ORTHAL.pdf).
Notably the differences are - the letters X & Y are not a part of the alphabet with the digraph KS & letter J replacing them in ORTHAL.
The vowels are indicated by the following different set of letters. With umlauted letters following standard German orthography/phonology for the most part. Vowels with the grave accent indicating changes from standard German orthography/phonology.
Presumably to allow for better readability/etymological link with standard German. Their publications E.g. - glossaries for children - http://www.olcalsace.org/fr/lexiques exemplifies the use of this orthography.
|IPA||/ɛ/||/ɑ ~ ɒ/||/æ/||/ɪ/||/œ/||/y/||/u/|
It seems that either the Wikipedia article is wrong or outdated. I can update Wikipedia, but before I update the article, I wanted to find out if there is an authoritative source for the orthography besides olcalsace.