You can answer such questions by insisting that poetry install the latest version of the project that you expect to be updated eg poetry add "pycron>=3.1.1"

Then one of three things will happen:

• poetry will refuse to make that change and will tell you the conflict that prevents it from doing so
• poetry will make the change: but to make that work it will have to downgrade something else. This happens when the latest versions of two packages conflict in some way, but a solution can be found by downgrading either one of them.
• (very unlikely) poetry will make the change without downgrading anything else, and you will still be confused about why it did not do so in the first place