version_compare()

version_compare() — Compares two “PHP-standardized” version number strings.

version_compare() — The function first replaces _, – and + with a dot . in the version strings and also inserts dots . before and after any non number so that for example ‘4.3.2RC1’ becomes ‘4.3.2.RC.1’. Then it compares the parts starting from left to right. If a part contains special version strings these are handled in the following order: any string not found in this list < dev < alpha = a < beta = b < RC = rc < # < pl = p. This way not only versions with different levels like ‘4.1’ and ‘4.1.2’ can be compared but also any PHP specific version containing development state.

Inputs: version1: First version number. version2: Second version number. operator: An optional operator. The possible operators are: <, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne respectively. This parameter is case-sensitive, values should be lowercase.

Returns: By default, 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. When using the optional operator argument, the function will return true if the relationship is the one specified by the operator, false otherwise.