In 2012 China revised its official guidelines for writing Pinyin.
These are the Hanyu Pinyin Zhengcifa Jiben Guize (official translation: “Basic Rules of the Chinese Phonetic Alphabet Orthography”), promulgated as GB/T 16159-2012.
Among the changes are that some alternate forms are now allowed, for example “wo de” (my) may also be written as “wode”. I’m not thrilled about that; but I know some people will welcome this.
I’ve added a few notes, such as for errors in the original document.
So far I have made only a version in so-called simplified Chinese characters. But eventually I’ll add one in traditional Chinese characters and an English translation.