Please keep in mind, that
openaip.net is not intended to support IFR-flights.
It is not affordable to keep all data every time up to date. This page is updated on a non regularly basis by volunteers around the world.
Some countries are updated every AIRAC cycle, some not and there are some countries which have not been updated since decades.
Feel free to add the ILS frequencies (directly at the RWY data at the airport), but don´t expect that this data is up to date at all airports.
And there is a problem, that only 1 frequency per RWY is possible. At least Frankfurt (EDDF) has 2 different ILS-frequencies for RWY 25R/07L
Peter