composer semantic meaning
"require": {
"vendor/package": "1.3.2", // exactly 1.3.2
// >, <, >=, <= | specify upper / lower bounds
"vendor/package": ">=1.3.2", // anything above or equal to 1.3.2
"vendor/package": "<1.3.2", // anything below 1.3.2
// * | wildcard
"vendor/package": "1.3.*", // >=1.3.0 <1.4.0
// ~ | allows last digit specified to go up
"vendor/package": "~1.3.2", // >=1.3.2 <1.4.0
"vendor/package": "~1.3", // >=1.3.0 <2.0.0
// ^ | doesn't allow breaking changes (major version fixed - following semver)
"vendor/package": "^1.3.2", // >=1.3.2 <2.0.0
"vendor/package": "^0.3.2", // >=0.3.2 <0.4.0 // except if major version is 0
}