Delphi 2007 - Compile errors on updating Indy from 10.5.1.1 to 10.6.2.0 - delphi

Question

I recently updated the stock Indy that installs with Delphi 2007 (I think it is 10.5.1.1) with 10.6.2.0, which I downloaded from GitHub.
I'm now getting a compile error:
EAttachmentFileNotFound.IfFalse (FileExists (parActualAttachmentFileID), 'File ' + parActualAttachmentFileID + ' not found.') ;
Error: E2003 Undeclared identifier: 'IfFalse'
The fragment is from my own code but I'm pretty sure that bit came from something I found probably on S/Overflow.
I received a couple of other errors also:
SMTPClient.AuthType := atDefault ;
Error: E2003 Undeclared identifier: 'atDefault'
and
SMTPClient.OnWork := EmailThread.EmailOnWork ;
Error: E2010 Incompatible types: 'Int64' and 'Integer'
but the first is a member that was renamed, and the second a data type that was changed. While these were a simple enough workaround, I'm left wondering
whether there was ever a "breaking changes" document generated.
maybe I accidentally somehow got the wrong source set.

Answer 1

EAttachmentFileNotFound is not a standard Indy exception, so it must be coming from your own code, or another 3rd party library.
Delphi 2007 was released almost 16 years ago. A lot has changed in Indy during that time. In fact, I think the changes you mention were actually made prior to, or maybe around, the release of Delphi 2007 (as they already existed in Indy's code in early 2008).
For instance:
in EIdException, the If(True|False) methods were removed (I don't know when exactly that change happened). In which case, you will have to use your own if and raise expressions now, eg:
if not FileExists(parActualAttachmentFileID) then
raise EAttachmentFileNotFound.Create('File ' + parActualAttachmentFileID + ' not found.');
in TIdComponent, the AWorkCount/Max parameters of the OnWork... events were changed from Integer to Int64 in 2006 (see OnWork Events changed to 64 bit on Indy's blog).
in TIdSMTP, the atDefault value was renamed to satDefault (again, I don't know exactly when this change was made).
So, you need to update your code accordingly.
I'm left wondering whether there was ever a "breaking changes" document generated.
No such document was ever created, no. However, changes that affect user code are typically announced on Indy's blog, under the Changelog category.