Thanks for the answer.
> Janus writes:
>
>> I have encountered some problems using org-drill. At the end I found that
>> the 'org-drill.el' version in the repository
>> https://code.orgmode.org/bzg/org-mode.git is 2.4.7.
>> The version on https://bitbucket.org/eeeickythump/org-drill/src/01b05cd7561a
>> is 2.6.1.
>>
>> Version 2.4.7 doesn’t work.
>>
>> Version 2.6.1 work perfectly.
>>
>> Do I miss something?
>
> It's up to the Org Drill maintainer to update their project in the
> contrib/ directory. If the project lives elsewhere, you may also want to
> ask its maintainer to remove it from contrib/ altogether.
>
reported in
https://bitbucket.org/eeeickythump/org-drill/issues/59/org-drill-version-is-outdated-in-org-mode
Best regards,
J