As you may know, the current format of the EMDB accession code is EMD-#### (4 digits starting at 1001).
Due to rapid growth, EMDB is running out of 4 digit accession codes. In the coming weeks, EMDB entries will be released with accession codes in the range below 1001 but padded with leading zeros to 4 digits, e.g., EMD-0011 or EMD-0221. Once the ids below 1001 are exhausted, assignments will continue with 5 or more digits.
EMDB accession codes will therefore have a variable format for their numerical portion: EMD-#### for 0001 through 9999, EMD-##### for 10000 through 99999, and, in the future, EMD-###### for 100000 and beyond.
Sources: 3DEMList-005864, 3DEMList-005867