Comment Notary (Score 1) 633
Take same measure as for last will.
And if you really want to save it in digital format - make agreement with notary to make every year copy of that CD/Disk/Whatever to DVD/Holodisc or whatever will be normally used that year. After 17 year you will end with 17 copies and few recent should be readable without problem. And you will have 16 backup copies.