Are hallucinations a requirement for Schizophrenia? The symptom most people think about when hearing "Schizophrenia" is hallucination. However, ICD-10's entry for schizophrenia seems to list auditory hallucinations as just one of many possible symptoms.

In practice, are hallucinations a required symptom for a diagnosis of Schizophrenia, or can a diagnosis be made based on other symptoms?
No – at least, they shouldn't be required. Wikipedia describes the DSM-5 as requiring "delusions, hallucinations, or disorganized speech". Delusions are distinct from hallucinations in that they aren't necessarily perceptual in a conventional sense, though both diverge a person's conscious experience from empirical reality. Disorganized speech is characteristic of disorganized / hebephrenic schizophrenia, regarding which Wikipedia states:


  The most prominent features of disorganized schizophrenia are not delusions and hallucinations, as they are in paranoid schizophrenia,[5][6] although fragmentary delusions and hallucinations may be present.


This doesn't seem to be the only (partial) exception to the rule you ask about, and your source mentions it too: "Affective changes are prominent, delusions and hallucinations fleeting and fragmentary".