Cross-compatible VSFF connection systems include optical connectors that are compatible with at least two types of adapters and adapters that are compatible with at least two types of optical connectors. Optical connectors have one or both of connector latch recesses and depressible latches, and likewise adapters have one or both of adapter latch arms and adapter latch recesses. Dual latch function connectors and adapters are capable of connection to a mating components that have only one type of latch structure, e.g., only recesses or only latches. Connection systems can be duplex or MT and may facilitate push-pull boot remote release and polarity change.