QGIS 3.4. This method has no effect, and is dangerous to call in earlier QGIS versions. Any usage should be removed (and will have no harmful side-effects!).
QGIS 3.10. We encourage you to use EPSG code or WKT to describe CRSes in your code wherever possible. Internal QGIS CRS IDs are not guaranteed to be permanent / involatile, and Proj strings are a lossy format.
QGIS 3.10. Use alternative methods for SRS construction instead – this method was specifically created for use by the postgres provider alone, and using it elsewhere will lead to subtle bugs.
QGIS 3.10. We encourage you to use EPSG codes or WKT to describe CRSes in your code wherever possible. Internal QGIS CRS IDs are not guaranteed to be permanent / involatile, and Proj strings are a lossy format.
QGIS 3.40. This signal is dangerous and extremely unsafe! It is recommended to instead set the useUnsafeSignals parameter to false in the QgsGpsDetector constructor and use the safe connectionDetected() signal instead.