One reason to move sooner rather than later is to mitigate the threat of previously stored data. There may be a government entity simply storing all imessage tr

One reason to move sooner rather than later is to mitigate the threat of previously stored data. There may be a government entity simply storing all imessage traffic in the hopes of one day decrypting it when/if a breakthrough happens. If you transition sooner, you increase the age of the latest data that could be decrypted, thusly hopefully making it safer.