Compatibility question

Hello,

I am the author of [Garage](https://garagehq.deuxfleurs.fr), a storage system that relies on `rmp-serde` to serialize all data that is persisted to disk. We are currently using version 0.15.5 of `rmp-serde`, and I am reluctant to upgrade to version 1.1.2 due to potential compatibility issues with existing data.

My questions are as follows:

- Is there a guarantee that all structures serialized with version 0.15.5 can always be deserialized with version 1.1.2?
- Do you recommend updating our `rmp-serde` dependency?

I know that the other way around (deserializing data using 0.15.5 that was serialized by 1.1.2) it doesn't always work, we accidentally ended up in such a situation and got error messages like this one: `Messagepack decode error: wrong msgpack marker FixStr(10)`

Thank you for your time and for making this project.