| # Change Log and Backward Compatibility | |
| ### Releases | |
| See release logs at | |
| [https://github.com/facebookresearch/detectron2/releases](https://github.com/facebookresearch/detectron2/releases) | |
| for new updates. | |
| ### Backward Compatibility | |
| Due to the research nature of what the library does, there might be backward incompatible changes. | |
| But we try to reduce users' disruption by the following ways: | |
| * APIs listed in [API documentation](https://detectron2.readthedocs.io/modules/index.html), including | |
| function/class names, their arguments, and documented class attributes, are considered *stable* unless | |
| otherwise noted in the documentation. | |
| They are less likely to be broken, but if needed, will trigger a deprecation warning for a reasonable period | |
| before getting broken, and will be documented in release logs. | |
| * Others functions/classses/attributes are considered internal, and are more likely to change. | |
| However, we're aware that some of them may be already used by other projects, and in particular we may | |
| use them for convenience among projects under `detectron2/projects`. | |
| For such APIs, we may treat them as stable APIs and also apply the above strategies. | |
| They may be promoted to stable when we're ready. | |
| * Projects under "detectron2/projects" or imported with "detectron2.projects" are research projects | |
| and are all considered experimental. | |
| * Classes/functions that contain the word "default" or are explicitly documented to produce | |
| "default behavior" may change their behaviors when new features are added. | |
| Despite of the possible breakage, if a third-party project would like to keep up with the latest updates | |
| in detectron2, using it as a library will still be less disruptive than forking, because | |
| the frequency and scope of API changes will be much smaller than code changes. | |
| To see such changes, search for "incompatible changes" in [release logs](https://github.com/facebookresearch/detectron2/releases). | |
| ### Config Version Change Log | |
| Detectron2's config version has not been changed since open source. | |
| There is no need for an open source user to worry about this. | |
| * v1: Rename `RPN_HEAD.NAME` to `RPN.HEAD_NAME`. | |
| * v2: A batch of rename of many configurations before release. | |
| ### Silent Regressions in Historical Versions: | |
| We list a few silent regressions, since they may silently produce incorrect results and will be hard to debug. | |
| * 04/01/2020 - 05/11/2020: Bad accuracy if `TRAIN_ON_PRED_BOXES` is set to True. | |
| * 03/30/2020 - 04/01/2020: ResNets are not correctly built. | |
| * 12/19/2019 - 12/26/2019: Using aspect ratio grouping causes a drop in accuracy. | |
| * - 11/9/2019: Test time augmentation does not predict the last category. | |