The fourth week of July has been exciting for the blockchain and cryptocurrency world. Perhaps the biggest news is that controversial Tron (TRX) chief executive Justin Sun gave a public apology on social media for his recent conduct to hype a cryptocurrency industry event. Sun wrote a letter in Mandarin on Weibo Thursday, saying he sincerely apologizes to the public, media, officials, and regulatory authorities for over-marketing and publicizing a highly-anticipated charity lunch with billionaire investor Warren Buffett of Berkshire Hathaway (BRK.A  ) fame. Sun did not specify which Chinese regulators he is referring. The letter came days after he postponed the lunch with Buffett, citing a health issue with kidney stones. It is unclear when the charity lunch between Sun and Buffett will be rescheduled.

Here is the rest of the week in review:

The US Internal Revenue Service (IRS) announced Friday that it is sending warning letters to taxpayers who own cryptocurrency, advising them to pay back taxes they may owe or to file amended income tax returns. In a news bulletin, the agency said that it began mailing what it called "educational letters" last week. The IRS disclosed that it sent letters to more than 10,000 taxpayers whose names were obtained from compliance efforts. IRS Commissioner Charles Rettig said that taxpayers should take these letters very seriously by reviewing their tax filings. He added that the IRS is expanding its enforcement involving virtual currency, including with data analytics. He said the agency wants to help taxpayers better understand their crypto tax obligations. A few users in the crypto subreddits posted about receiving such a letter.

Huawei chief executive Ren Zhengfei called on China to preempt Facebook's (FB  ) Libra stablecoin project. The telecommunications giant's head said that the time is ripe for China's government to take advantage of Facebook's regulatory hurdles and create a Chinese stablecoin. In an interview with Italian media outlet L'economia, Ren asserted that China has the ability to pursue a successful stablecoin. Some Chinese central bank members have worried that Libra's debut could negatively impact the country even though Facebook is banned there. But Wang Xin, the central bank's head of the research bureau, believes the competition could push China to form and issue its own national cryptocurrency.

Crypto prices moderately slipped to $264 billion. For the majors, all but Tether (USDT) and EOS ended up in the red, with bad losses posted by Bitcoin SV (BSV), Litecoin (LTC), Bitcoin (BTC), and Binance Coin (BNB). In the top 100, the biggest losers were Metaverse ETP (ETP), down a sharp 32%, Bitcoin Gold (BTG), down 27%, and Aurora (AOA), down 25%. The biggest gainers were UnlimitedIP (UIP), up a whopping 209%, Ren (REN), up 31%, and Nash Exchange (NEX), up 20%. Next week traders will watch if Bitcoin can break through the key $10,000 level again.

The author owns a small amount of BTC and LTC.