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I am doing a very simple example, but keep getting the message `AttributeError: 'Flow' object has no attribute 'serve'`.

Hey <@U03GN1YA7AA>! What version of `prefect` do you have installed? Sharing the output of `prefect version` would be great!

```Version:             2.82
API version:         0.8.4
Python version:      3.9.14
Git commit:          afbed19d
Built:               Fri, Feb 17, 2023 10:02 AM
OS/Arch:             darwin/arm64
Profile:             default
Server type:         cloud```

Whereby the Prefect version in my deps file is `prefect = "^2.13"`

```python = "&gt;=3.9,&lt;3.11"
requests = "^2.27.1"
prefect = "^2.13"
prefect-dask = "^0.2.5"
redis = "^4.1.1"
cleo = "^0.8.1"
boto = "^2.49.0"
boto3 = "^1.22.4"
scipy = "^1.8.1"
plotly-express = "0.4.0"
kaleido = "0.2.1"
markdown = "3.3.7"
sendgrid = "6.9.7"
pydantic = "&lt;2.0.0"```

Thanks! Are you using `poetry`? I remember seeing another user that used `poetry` that had a similar issue and a similar `prefect version` output.

Yes, but it shouldn’t make any difference, right? It just installs the deps to a virtualenv.

The most recent version of `prefect` is `2.13.5`, but `poetry` installed a version that is nearly eight months old, which is why `.serve` isn’t working for you.

BTW: Maybe unrelated. I realized that I had to pin the `pydantic` version because the CLI would otherwise not work as expected. It seems that at least one of my other dependencies does refer to a newer version because I didn’t have `pydantic` listed as an explicit dependency before.

Ah, if you pinned `pydantic` then that might cause this behavior. Can you share the error that you saw from the CLI?

`ImportError: cannot import name 'SecretField' from 'pydantic'`

I am updating to `2.13.5` now and also removed the hardcoded `pydantic` version from my Poetry environment … so fingers crossed.

Just for reference, what version of `poetry` are you using?

OK, it seems to work now. I am right now upgrading an older Prefect 1.x project to 2.x and had to do a bunch of things to get it working:

1. I am now using version 2.13.5 of Prefect

2. The Poetry version was also outdated. I was on 1.1 which caused that `poetry update` ended up in an endless loop :shrug:, so I am now using Poetry 1.6.1.

The `serve` function works now as expected. Thanks!