sbbslist.js Error: can't convert options.backup_level to an integer

sbbslist.js missing default value for backup_level.

current modopts.ini:

[sbbslist]
    export_freq = 7
    add_ars = not guest

Jan 27 00:00:00 scarlet synchronet: evnt SBL2HTML Executing external: ?sbbslist html
Jan 27 00:00:00 scarlet synchronet: evnt SBL2HTML Opening list file: /sbbs/data/sbbslist.json
Jan 27 00:00:00 scarlet synchronet: evnt SBL2HTML !JavaScript  /sbbs/exec/sbbslist.js line 2437: Error: can't convert options.backup_level to an integer
Jan 27 00:00:00 scarlet synchronet: evnt SBL2IMSG Executing external: ?sbbslist imsglist
Jan 27 00:00:00 scarlet synchronet: evnt SBL2IMSG Opening list file: /sbbs/data/sbbslist.json
Jan 27 00:00:00 scarlet synchronet: evnt SBL2IMSG !JavaScript  /sbbs/exec/sbbslist.js line 2470: Error: can't convert options.backup_level to an integer