Yes, you can connect to a 10.4.x geodatabase using ArcGIS Desktop 10.7 and copy data into another 10.7 geodatabase.
If your aim is to upgrade the 10.4 geodatabase, even that is possible from ArcGIS Desktop 10.7 directly. I am not aware which DBMS you are using, but here is a link for SQL Server databases. You similarly have links for other RDBMSs:
You can upgrade directly from a 10.2.x, 10.3.x, 10.4.x, 10.5.x, 10.6.x, or 10.7 geodatabase if your database is at a supported release.
Thanks for the reply, I'm aware of the upgrade procedure for a geodatabase, but was just curious if it was effectively the same thing to copy data from an older version to a newer version. I would sort of like to test the curve data especially since I know there was an issue with curves upgrading from 10.4 to 10.5 but I believe that may have been corrected in later upgrades.
The upgrade and copy to a new enterprise geodatabase (EGDB) are not the same. It is possible to do either.
Upgrade = keep everything in tack and place (permissions, versioning, replicas, etc.) and bring it to the latest version.
Copy to new EGDB = Copy the data to a new GDB via ArcGIS Desktop client. This will NOT bring over the permissions, all the versions of data and/or replica information (if you have that enabled and in use). This will also not include any special keyword configurations that you have in the older EGDB.
When you copy over the data it will bring over the data version that is copied. You will have to do more configuration on the "new" EGDB once the copy is complete.
My follow up questions is this: What is the thought behind coping the data over to a new EGDB vs. Upgrade in place? T
That may help with some of the response.
The way curves are stored has changed since 10.4, as I stated above was looking for a way to test before performing an upgrade on the original EGDB. That is my reason, but also wondering what happens should I decide to import some data after the upgrade. I'm curious about how ArcGIS Pro determines the version when using it to create a file or Enterprise GDB, by the portal you login through or the version of desktop installed on the local computer, if there is one. It is difficult to test this, I haven't figured out how to view the actual release version, since properties in ArcCatalog simply state it matches the client version, and GDB properties don't seem to be available in the context menu of Pro.
Thanks for the context. You could create a new EGDB with the latest Pro version (2.4.1 as of today) and then copy the data into it and do your testing. The version of the EGDB (or file GDB) is determined on the version of the client used to create it. For example, if you create the EGDB with ArcGIS Pro 2.4.1 it will be that version. You are still able to connect with ArcMap 10.7.1, if needed
If you upgrade the existing EGDB, I am not sure that it will update the way the current curves are stored. That may be a question for technical support.
If the client says that the EGDB matches the client version then it is at least that clients version or newer. You could query the version table in the RDBMS; Example: Finding the geodatabase release using SQL—Help | ArcGIS Desktop