**Highlights**
- Support LFB
- Support using backbone from MMCls/TorchVision
- Add Chinese documentation
**New Features**
- Support LFB ([553](https://github.com/open-mmlab/mmaction2/pull/553))
- Support using backbones from MMCls for TSN ([679](https://github.com/open-mmlab/mmaction2/pull/679))
- Support using backbones from TorchVision for TSN ([720](https://github.com/open-mmlab/mmaction2/pull/720))
- Support Mixup and Cutmix for recognizers ([681](https://github.com/open-mmlab/mmaction2/pull/681))
- Support Chinese documentation ([665](https://github.com/open-mmlab/mmaction2/pull/665), [#680](https://github.com/open-mmlab/mmaction2/pull/680), [#689](https://github.com/open-mmlab/mmaction2/pull/689), [#701](https://github.com/open-mmlab/mmaction2/pull/701), [#702](https://github.com/open-mmlab/mmaction2/pull/702), [#703](https://github.com/open-mmlab/mmaction2/pull/703), [#706](https://github.com/open-mmlab/mmaction2/pull/706), [#716](https://github.com/open-mmlab/mmaction2/pull/716), [#717](https://github.com/open-mmlab/mmaction2/pull/717), [#731](https://github.com/open-mmlab/mmaction2/pull/731), [#733](https://github.com/open-mmlab/mmaction2/pull/733), [#735](https://github.com/open-mmlab/mmaction2/pull/735), [#736](https://github.com/open-mmlab/mmaction2/pull/736), [#737](https://github.com/open-mmlab/mmaction2/pull/737), [#738](https://github.com/open-mmlab/mmaction2/pull/738), [#739](https://github.com/open-mmlab/mmaction2/pull/739), [#740](https://github.com/open-mmlab/mmaction2/pull/740), [#742](https://github.com/open-mmlab/mmaction2/pull/742), [#752](https://github.com/open-mmlab/mmaction2/pull/752), [#759](https://github.com/open-mmlab/mmaction2/pull/759), [#761](https://github.com/open-mmlab/mmaction2/pull/761), [#772](https://github.com/open-mmlab/mmaction2/pull/772), [#775](https://github.com/open-mmlab/mmaction2/pull/775))
**Improvements**
- Add slowfast config/json/log/ckpt for training custom classes of AVA ([678](https://github.com/open-mmlab/mmaction2/pull/678))
- Set RandAugment as Imgaug default transforms ([585](https://github.com/open-mmlab/mmaction2/pull/585))
- Add `--test-last` & `--test-best` for `tools/train.py` to test checkpoints after training ([608](https://github.com/open-mmlab/mmaction2/pull/608))
- Add fcn_testing in TPN ([684](https://github.com/open-mmlab/mmaction2/pull/684))
- Remove redundant recall functions ([741](https://github.com/open-mmlab/mmaction2/pull/741))
- Recursively remove pretrained step for testing ([695](https://github.com/open-mmlab/mmaction2/pull/695))
- Improve demo by limiting inference fps ([668](https://github.com/open-mmlab/mmaction2/pull/668))
**Bug and Typo Fixes**
- Fix a bug about multi-class in VideoDataset ([723](https://github.com/open-mmlab/mmaction2/pull/678))
- Reverse key-value in anet filelist generation ([686](https://github.com/open-mmlab/mmaction2/pull/686))
- Fix flow norm cfg typo ([693](https://github.com/open-mmlab/mmaction2/pull/693))
**ModelZoo**
- Add LFB for AVA2.1 ([553](https://github.com/open-mmlab/mmaction2/pull/553))
- Add TSN with ResNeXt-101-32x4d backbone as an example for using MMCls backbones ([679](https://github.com/open-mmlab/mmaction2/pull/679))
- Add TSN with Densenet161 backbone as an example for using TorchVision backbones ([720](https://github.com/open-mmlab/mmaction2/pull/720))
- Add slowonly_nl_embedded_gaussian_r50_4x16x1_150e_kinetics400_rgb ([690](https://github.com/open-mmlab/mmaction2/pull/690))
- Add slowonly_nl_embedded_gaussian_r50_8x8x1_150e_kinetics400_rgb ([704](https://github.com/open-mmlab/mmaction2/pull/704))
- Add slowonly_nl_kinetics_pretrained_r50_4x16x1(8x8x1)_20e_ava_rgb ([730](https://github.com/open-mmlab/mmaction2/pull/730))