Software that allows entities from one virtual world to communicate meaningfully with those from another by adapting their form and other attributes.
For many types of virches, and particularly ones which have a lot of contact with other virches, regardless of the differences between them, over time there have evolved pieces of software to interface, translate and/or emulate between virches and so, as long as each virch world allows such software the leeway to function within it (normally only after an extremely thorough examination to ensure it does not contain any harmful viruses and other undesirables), allow virch entities from one world to exist and communicate meaningfully with those from the other. This software is usually included in the exoself of the traveler, and is usually known as an Emulation Suit. Most of this type of software is of a relatively simple type, in that it allows the translation/emulation of an entity from one virch in one or more specified other virch environments, with all of the required translations 'hard-wired' in.
The existence of such software is not the case between all virches of course, but there are also exoself software packages for virch travelers and tourists which will provide 'virtual life support', allowing them to adapt to most types of new worlds as they go. This type of software requires some sort of dedicated processor, usually some form of specialized non-sentient super-Turing. They adapt to moving through different types of virches by various means, usually involving their scanning ahead to determine the properties of the virch they are heading for, then modifying its emulation/adaptation layer to handle the new virch. This type of software, while harder to create successfully, is the preferred type for the seasoned virch traveler.
This virch 'life support' includes protecting the sanity of the virch entity from any features of the world it is visiting that might harm it. Of course, depending on the quality of this software, the traveler may or may not be able to travel to certain types of virch.
It is not unknown for this exoself translation/emulation software to be sophont in its own right. This is one way in which AIs are known to trade with the inhabitants of various virches. Also, AIs have been known to 'work their passage' through a number of virch worlds to their destination, acting as an emulator/translator controller for a traveling virch entity of some kind.
Similar interfacing, translation and/or emulation programs exist to cope with movement of software between different computing substrates (for example quantum-computing computronium and biogeocomputers) and operating systems which are, after all, still largely descended from binary computing systems. These tend to be part of the computing system itself rather than part of the exoself of the traveler. If a particular virch entity runs in a manner very different to that of the virch they are visiting, it may take a great deal more computing resources to allow them to run there than that required to run a native (normally the greater the difference, the greater the resource requirements for visitors).
Some virches may exclude travelers for this reason. Other virches where this is the case may simply charge the traveler for the privilege of using the extra computing cycles they require.