Invalid Formula: Unknown Function/Operator can be seen in the log.nsf database on the server and on the client. it can be seen as a pop up box.
If a database has been changed by a new version of the client e.g. 6.5 and you are using notes 5.03 then you will see this error.
If a server ets this error in the log.nsf the database version is newer than the server, upgrade the server!
Solution 1: upgrade to a newer client !
Solution 2: moan to the developer and tel them that it needs to revert back to using the older client.
Administrator Upgrade Strategies:
When upgrading, update servers first, this then allows web only apps to use the new features of the newer version of Lotus notes straight away.
Notes Clients can then be upgraded step by step.
NB: Upgrading clients from Notes 6 or Notes 6.5 to Notes 7 is very easy and should be relatively painless.
Designer Strategies for preventing Version problems
You can use the database suffixes to prevent use of newer design elements:
Change a database to database.ns5 or database.nt5 to let your 6.5 or above designer client know not to let you use newer elements.
This works with .ns4 .nt4 ns7 and nt7 as well.