The four statutory release forms: conditional or unconditional, progress or final, and the one you must never sign before the check clears
In one paragraph
California lets you sign away lien, stop notice and payment bond rights only on four forms whose text is written into the Civil Code: conditional or unconditional, on a progress payment or on final payment. A conditional release costs you nothing until the check clears. An unconditional release gives up the rights the moment you sign it, whether or not you are ever paid, and the form says so in capital letters. Homeowners are told in their own contract to demand releases; GCs demand them on every draw. Here is which form to sign when, and the one rule that has no exceptions.
The rule
A waiver and release does not release the owner, lender or surety unless it is in substantially the statutory form and signed, and, if conditional, there is evidence of payment (Civil Code 8124); any other statement waiving lien rights is void unless the claimant has actually been paid in full (8126). The four forms are the Conditional Waiver and Release on Progress Payment (8132), Unconditional on Progress Payment (8134), Conditional on Final Payment (8136) and Unconditional on Final Payment (8138). The unconditional forms carry the statutory notice that they are enforceable against you if you sign them even if you have not been paid.
Why it matters
Signing an unconditional release to 'speed up the check' and then not receiving the check is the classic way a subcontractor loses a job's payment with no lien to fall back on; the statute prints the warning on the form in capitals because it happens constantly. Using the conditional form instead costs nothing and protects everything.