I installed qemu using apt and got version 2.11.
Decided to use a more recent version and downloaded the source for 4.0.
Removed apt version with a:

```
apt remove qemu

```

successfully compiled version 4.0, but running "--version" results in version 2.11:

```
$ qemu-system-x86_64 --version
QEMU emulator version 2.11.1(Debian 1:2.11+dfsg-1ubuntu7.13)
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

```

have I removed it wrongly? will I have to compile it again? It took so much time...