Many FOSS projects start out without a Contributor License Agreement (CLA). Many, if they become large and successful, will want to transition to system based on CLAs. But what about if they can't track down all of the old contributors? I can think of three possibilities:
- They can continue without the contributors signing the CLA and proceed to change the license etc with the hope that the contributors will be found in the future
- They can rewrite all code contributed by them
- They can keep the existing license until all contributors have signed their CLAs
Is the first option possible or do such projects need to choose between the second and third?