whene update cli from 3.3 to 3.4 i have many error. ionic old version is very very better than new version.
look how im working
step 1:
ionic start myApp tabs
this is worked.
step 2:
ionic info
thats greate. 
step 3:
ionic cordova plugin add cordova-plugin-camera
ooooopps not worked. then i try
ionic serve
show me below error
then i search in internet to find solution and try below
1- npm install.
2- delete node_modules then npm install
3- npm cache clean --force
How did you update Ionic CLI?
What is your ionic info output?
What errors did you get in step 3?
try…
ionic plugin add cordova-plugin-camera
for example when i run ionic info tell me update available do you want update? and i accept it.
erro in step 3
Attention :
any time error is different
1- ionic-angular
2- ionic-icons
…
Some program is blocking your node_modules folder.
Are you running VSCode 1.13? That had a bug that blocked the node_modules folder, update to 1.14 or close it while doing npm stuff. Anything else running that could be blocking your node_modules?
thank you . i find solution when i want install plugin i must exist from ionic serve and close anything because node.module run by nodejs
