When was the release date of Buddhism?

Generally, we call the day when Sakyamuni Buddha was born, that is, the eighth day of April, as the bathing Buddha release festival. But don't stick to this, because doing good deeds, regardless of time and place ~ because once a day is regarded as a birthday, those who sell birds, insects, fish and shrimp will catch more animals to sell, but they will create bad karma. Therefore, it is common to release people on the fifteenth day of the first month. This brother's answer is correct and can be used.