Original: The paper claims that the probability of truncated differentials is 2-57 .3 per block and that it will take roughly 251 chosen plaintexts (32 petabytes worth of data) to find a good pair of truncated differentials.
Simplified: The paper claims that the probability of truncated differentials attacks is 2-57 .3 per block and that it will take about 251 chosen plaintexts (32 PiB worth of data) to find a good pair of truncated differentials.