Update README.md

README.md

 English | [简体中文](README_cn.md)
 
-## **Live stream**:  July 21, 2020 at 8 pm BiliBili station，PaddleOCR Introduction
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-**Live address：https://live.bilibili.com/h5/21689802**
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 ## Introduction
 PaddleOCR aims to create rich, leading, and practical OCR tools that help users train better models and apply them into practice.
 
 **Recent updates**
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+- 2020.7.21, Release the playback and PPT of live class on BiliBili station, PaddleOCR Introduction, [address](https://aistudio.baidu.com/aistudio/course/introduce/1519)
 - 2020.7.15, Add mobile App demo , support both iOS and  Android  ( based on easyedge and Paddle Lite)
 - 2020.7.15, Improve the  deployment ability, add the C + +  inference , serving deployment. In addtion, the benchmarks of the ultra-lightweight OCR model are provided.
 - 2020.7.15, Add several related datasets, data annotation and synthesis tools.