Elon Musk tweeted last week that Tesla would be unveiling a product "unexpected by most" on Oct. 17. On Sunday, however, the Tesla chief announced on Twitter that the launch had been moved to Wednesday as the product needed more refinement.

The product is being kept under wraps by Tesla and it is not clear what product the company plans to unveil or what refinements the it is working on. There has been speculation that the unveiling could be that of the Model 3 electric car, along with Autopilot 2.0 semi-autonomous driving system. With the launch of Autopilot 2.0, Tesla is expected to add more sensors to its cars and provide the vehicle more self-driving features.

The first version of Autopilot released in October 2015, and the second one is releasing a year after the original.

Apart from this, Musk also tweeted on Sunday about a photovoltaic cell and module production facility in Buffalo, New York, in collaboration with Panasonic.

“We are excited to expand our partnership with Panasonic as we move towards a combined Tesla and SolarCity. By working together on solar, we will be able to accelerate production of high-efficiency, extremely reliable solar cells and modules at the best cost.”, said JB Straubel, chief technical officer and co-founder, Tesla, in an official press release announcing the collaboration Sunday.

Tesla’s $2.6 billion merger with SolarCity has yet to be approved by shareholders. Under the agreement, Tesla will use the cells and modules in solar energy system and will work seamlessly with Powerwall and Powerpack, Tesla’s energy storage products. While the launch takes place on Oct. 28, shareholders vote on the proposed launch on Nov. 17.