root@jacob2:/# apt-get install curl
Reading package lists... Done
Building dependency tree
Reading state information... Done
curl is already the newest version (7.64.0-4).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@jacob2:/# apt-get install php7.3-curl
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 php7.3-curl : Depends: libcurl3 (>= 7.44.0) but it is not installable
E: Unable to correct problems, you have held broken packages.
root@jacob2:/# sudo apt remove libcurl4
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  apache2-data libaprutil1-dbd-sqlite3 libaprutil1-ldap libbrotli1 liblua5.2-0
  libpython2.7 libuv1 python-dnspython ruby-rack
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
  apache2 apache2-bin apache2-suexec-pristine clamav curl libapache2-mod-fcgid
  libapache2-mod-passenger libapache2-mod-php libapache2-mod-php5.6
  libapache2-mod-php7.0 libapache2-mod-php7.1 libapache2-mod-php7.2
  libapache2-mod-php7.3 libapache2-mod-python libcurl4 mailman passenger
0 upgraded, 0 newly installed, 17 to remove and 0 not upgraded.
After this operation, 76.3 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 81682 files and directories currently installed.)
Removing mailman (1:2.1.29-1) ...
Removing apache2 (2.4.38-3) ...
Removing libapache2-mod-php (2:7.3+70+0~20190814.17+debian9~1.gbp1e7da2) ...
Removing libapache2-mod-php7.3 (7.3.8-1+0~20190807.43+debian9~1.gbp7731bf) ...
Removing libapache2-mod-php7.2 (7.2.21-1+0~20190807.25+debian9~1.gbp935ebf) ...
Removing libapache2-mod-php7.1 (7.1.31-1+0~20190807.22+debian9~1.gbpf402ed) ...
Removing libapache2-mod-php7.0 (7.0.33-10+0~20190807.18+debian9~1.gbp5452d8) ...
Removing apache2-suexec-pristine (2.4.38-3) ...
Removing clamav (0.101.2+dfsg-1) ...
Removing curl (7.64.0-4) ...
Removing libapache2-mod-fcgid (1:2.3.9-4) ...
Removing libapache2-mod-passenger (5.0.30-1.1) ...
Removing libapache2-mod-php5.6 (5.6.40-10+0~20190807.18+debian9~1.gbp5642bf) ...
Removing libapache2-mod-python (3.3.1-11) ...
Removing passenger (5.0.30-1.1) ...
Removing apache2-bin (2.4.38-3) ...
Removing libcurl4:amd64 (7.64.0-4) ...
Processing triggers for man-db (2.8.5-2) ...
Processing triggers for libc-bin (2.28-10) ...
root@jacob2:/# sudo apt-get install  libcurl4
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  apache2-data libaprutil1-dbd-sqlite3 libaprutil1-ldap libbrotli1 liblua5.2-0
  libpython2.7 libuv1 python-dnspython ruby-rack
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
  libcurl4
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 332 kB of archives.
After this operation, 714 kB of additional disk space will be used.
Get:1 http://deb.debian.org/debian stable/main amd64 libcurl4 amd64 7.64.0-4 [332 kB]
Fetched 332 kB in 0s (1,039 kB/s)
Selecting previously unselected package libcurl4:amd64.
(Reading database ... 76838 files and directories currently installed.)
Preparing to unpack .../libcurl4_7.64.0-4_amd64.deb ...
Unpacking libcurl4:amd64 (7.64.0-4) ...
Setting up libcurl4:amd64 (7.64.0-4) ...
Processing triggers for libc-bin (2.28-10) ...
root@jacob2:/#