You can use your 25kHz radio on any remaining 25kHz frequencies during 2018, but only until they change to 8.33kHz channels, which you can’t use it on. After 01/01/19 it is dead weight, as all frequencies should be 8.33kHz channels by then.
Except they won't!
The following assignments will remain on 25 kHz permanently:
- 121.500 Emergency Frequency.
- 123.100 SAR Auxiliary Frequency.
- 122.100 NATO Combined Frequency.
- The VHF digital link frequencies 136,725 MHz, 136,775 MHz, 136,825 MHz, 136,875 MHz, 136,925 MHz and 136,975 MHz.
- The ACARS frequencies 131,525 MHz, 131,725 MHz and 131,825 MHz.
- Where offset carrier operation within a 25 kHz channel spacing is utilised (e.g. VOLMET).