This is not a new development or revelation fundamentally, actually, as it is based on a discourse the last leader of the Chabad-Lubavitch faith delivered before his passing over three decades ago. However, as other of their teachings delivered in their abstruse lingo, some of it specific to the Crown Heights sect, it can be difficult for the average person to grasp, especially if they have no background with them. A few years back Chabad had some special programming (e.g. this event with Lubavitch scholar Y.Y. Jacobson instructing the crowd in the subject) to break down, simplify, explicate, and disseminate it to the masses. However, even then, the target audience was their own group, leaving many normative Jews blissfully ignorant of the confused and deviant doctrines preached in a section of Brooklyn. Furthermore, Lubavitchers have a long history of deception, denial, obfuscation, and misdirection, with regard to some of their more problematic beliefs and practices.
Now, however, they have stepped up their dissemination of it, by putting out a booklet promoting it to children with simple language and colorful illustration.
‘The Mikdash Movement’ Book Highlights the Uniqueness of 770 - Anash.org
Tut Altz Kids - The Mikdash Movement SAMPLE.pdf (dropbox.com)
Viewing the sample pages online, one clearly sees that the publication teaches that 770 = Beis Hamikdash, and is Moshiach's Shul.
It is important to note that this booklet is not put out by a "meshichist" faction, but rather by the "establishment" Chabad-Lubavitch faction led by Krinsky, Kotlarsky, et al.
People need to be aware of such delusional, dangerous beliefs held by this aggressive group, the imperative therefore to keep a distance from them, and not mistakenly support or join with them out of ignorance.
In the zechus of rejection of false messianism, may we be zoche to a שנת גאולה וישועה, and the true משיח בקרוב.
כתיבה וחתימה טובה