The promise of the Chazon Ish is already famous - that missiles will not fall in Bnei Braq. Rav Chaim Kanievsky has quoted and used this promise in practice regarding questions of safety in Bnei Braq, in more than one war...

and now this promise has been extended..

Rav Chaim Kanievsky said regarding Modiin Ilit that the Chazon Ish's promise surely applies to that city as well. as it is a city mostly of Torah - yeshivas, kollels, schools, and the same promise surely applies there as well - missiles will not fall in Modiin Ilit.

Rav Kanievsky clarified that this is not a new promise of his, but it is the words of his uncle the Chazon Ish.
source: Bechadrei

Halevai it should be true. BH, so far so good. The Iron Dome has let very few missiles slip through at all, and none in Bnei Braq and Modiin Ilit,  so the promise has been working.

I think the people of Beitar, Rechasim, Beit Chilkiya, and any other charedi town (maybe even Bet Shemesh), should go to Rav Kanievsky and get the promise extended to their towns as well,  considering all such towns are largely centered around Torah institutions.... Theoretically it should also apply about towns that are Dati Leumi and focused around Torah as well, and perhaps he should also be asked about such towns...