Every function that takes a dwAPIVersion or similar parameter must set this parameter to either the highest API version supported by the application or the API version negotiated using the lineNegotiateAPIVersion or phoneNegotiateAPIVersion function on a particular device. Use the following table as a guide:
| Function | Meaning |
|---|---|
| lineGetAddressCaps | Use version returned by lineNegotiateAPIVersion. |
| lineGetCountry | Use highest version supported by the application. |
| lineGetDevCaps | Use version returned by lineNegotiateAPIVersion. |
| lineGetProviderList | Use highest version supported by the application. |
| lineGetTranslateCaps | Use highest version supported by the application. |
| lineNegotiateAPIVersion | Use highest version supported by the application. |
| lineNegotiateExtVersion | Use version returned by lineNegotiateAPIVersion. |
| lineOpen | Use version returned by lineNegotiateAPIVersion. |
| lineTranslateAddress | Use highest version supported by the application. |
| lineTranslateDialog | Use highest version supported by the application. |
| phoneGetDevCaps | Use version returned by phoneNegotiateAPIVersion. |
| phoneNegotiateAPIVersion | Use highest version supported by the application. |
| phoneNegotiateExtVersion | Use version returned by phoneNegotiateAPIVersion. |
| phoneOpen | Use version returned by phoneNegotiateAPIVersion. |
Important When negotiating an API version, always set the high and low version numbers to the range of versions that your application can support. For example, never use 0x00000000 for the low version or 0xFFFFFFFF for the high because these values require that your application support all versions of TAPI, both past and future.