Due to concerns about malicious applications, GPT2 will not be released (2019)

OpenAI developed GPT-2, a large-scale unsupervised language model with 1.5 billion parameters, trained on 8 million web pages. It generates coherent text and performs various language tasks without specific training, achieving state-of-the-art performance. GPT-2 is a scaled-up version of GPT, with over 10 times more parameters and data. OpenAI initially withheld its full release in 2019 due to concerns about potential malicious applications.