Following Classes are missing in new version:
com.reuters.tibmsg package itself is missing.
What are the new classes to be used instead of above?
The classes you mention above are for the legacy MarketData interface which supports the legacy string-based Marketfeed data format.
The v8.x of RFA only supports the newer OMM interfaces and more efficient binary RWF data format.
The most recent version of RFA Java that supports the legacy stuff is v7.6.x which can be downloaded from RFA Java - Older Versions
However, I would advise against the continued use of the legacy formats if at all possible.
And rather than upgrading to the v8 of RFA, I would recommend you consider migrating to the newer strategic Elektron SDK Java which also supports the newer OMM interfaces etc.
RFA v8 is feature complete, in maintenance mode only and will not receive any new features or enhancements other than bug fixes.
The ElektronSDK has numerous benefits of RFA including longer-term support, support for newer features, much easier to learn, easier to code, less coding and easier to maintain long term.