I looked around and I found these informations:
U2 first signed a record deal for 4 albums in 5 years,
then (before UF came out) they signed a record deal for 4 albums - this time with artistic freedom and the choice of producer, having all rights to their old and new songs,
then in '93 (before Zooropa came out) they signed a deal for 6 albums and 25% from the earnings of those albums,
but in '98 (when first Best of came out) that deal changed to 3 more albums and 1 more Best of.
U2 first signed a record deal for 4 albums in 5 years,
then (before UF came out) they signed a record deal for 4 albums - this time with artistic freedom and the choice of producer, having all rights to their old and new songs,
then in '93 (before Zooropa came out) they signed a deal for 6 albums and 25% from the earnings of those albums,
but in '98 (when first Best of came out) that deal changed to 3 more albums and 1 more Best of.