is this still active in development?

[chiraggmodi]

I believe this is discontinued,

so is there any alternative for this?

[wehdemeyer]

I think it's dead.
Errors in WordPress - due to the (updated) jQuery library...
Did you find an alternative?

[chiraggmodi]

Fancy box is good alternative for personal projects, but didn't find any good free open source for commercial

[syrsly]

You could always fork the project and update it yourself.