Phone software wasn't honest when put to use (7)
I believe the answer is:
applied
'put to use' is the definition.
(I've seen this in another clue)
'phone software wasn't honest' is the wordplay.
I cannot really understand how this works, but
'software' could be 'app' (software application) and 'app' is found in the answer.
'wasn't honest' could be 'lied' (told a lie) and 'lied' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'when' acts as a link.
Can you help me to learn more?
(Other definitions for applied that I've seen before include "Asked (for job); not pure (maths)" , "Useful" , "Was relevant" , "Put oneself forward, for a job say" , "implemented" .)