Because FileMaker Pro 7, 8.x, 9, and 10 do not recognize previously supported alphabetic characters in a number field as numbers, some logical functions that return Boolean true/false results may return the wrong results. Also, some find requests for Boolean content may return different results than in pre-7.0 versions of FileMaker Pro.
If you have used “Yes” or “T” or other text to mean true in number fields, Boolean calculations relying on these characters will not return results consistent with pre-7.0 versions of FileMaker Pro.
Find requests for Boolean information are also more restrictive. For example, in a pre-7.0 release of FileMaker Pro, a find request in a number field for True would find the values 1, True, Yes, Y, y, T, or t. In FileMaker Pro 7 8.x, 9, and 10, this find request would only find the value True. You can modify your find request to make the found set match what was returned in previous releases. You can also use the Find/Replace command to make your data consistent.