The Kids Of Degrassi Street
This logo was used for the original show which was only 26 episodes long, which ended in 1986.
Degrassi: Junior High
This logo was used for the 3 seasons of Degrassi Junior High, followed by Degrassi High.
They used this logo for 2 seasons of Degrassi High, which ended in 1991. After Degrassi High there wasn't any Degrassi until 10 years later when Degrassi: The Next Generation came to TV. Despite the TV movie "School's Out" that was released in 1992.
This was the movie that was released a little after the finale of Degrassi High...next was the premier of Degrassi: The Next Generation that premiered in 2001.
Degrassi: The Next Generation
This was the logo for the first 9 seasons of the show.