version_compare() compares two
"PHP-standardized" version number strings. This is useful if
you would like to write programs working only on some
versions of PHP.
version_compare() returns -1 if
the first version is lower than the second, 0 if they are
equal, and +1 if the second is lower.
If you specify the third optional
operator argument, you can test for a particular
relationship. The possible operators are: , lt, =, le, , gt, =, ge, ==, =, eq, !=, , ne
respectively. Using this argument, the function will return 1
if the relationship is the one specified by the operator, 0
otherwise.